The Open Civil Engineering Journal




ISSN: 1874-1495 ― Volume 13, 2019
RESEARCH ARTICLE

Development of Ductile Truss System Using Double Small Buckling-Restrained Braces: Analytical Study



Hidajat Sugihardjo*, Yudha Lesmana, Dwi Prasetya
Department of Civil Engineering, Institut Teknologi Sepuluh Nopember (ITS), Surabaya, Indonesia

Abstract

Introdution:

This paper proposed a Small Buckling-Restrained Brace (SBRB) for the ductile truss moment frames and is called here as the Double Braced Truss Moment Frames (DB-TMF). The braces are located at the edge of the truss girder and are only placed around the building perimeter. The braces work in pair as a weak element (structural fuses) and is expected to effectively absorb the seismic energy. The proposed DB-TMF system is an extended development of the Knee Braced Truss Moment Frames (KB-TMF). The DB-TMF system is expected to carry the whole seismic loads, while the rest of the frame is designed to carry only the gravity loads.

Methods:

To study the performance of the proposed DB-TMF system, non-linear finite element analysis was carried out using the DRAIN-2DX package. From the analysis with various time history records, it was found that the drift ratio of the DB-TMF system is lower than the allowed story drift. The roof-top displacement shows an asymptotic behavior. The shape of the hysteresis curve tends to have a pinching shape. However, the cumulative ductility of the proposed system satisfies the requirements as a hysteretic structure. In the event of an earthquake, only the SBRB and the chords adjacent to the column element are damaged while the rest of the structural elements remain elastic which is expected.

Results and Conclusion:

Based on the performance evaluation of the DB-TMF system, the DB-TMF system is suitable for moderate seismic region and has smaller dimension steel sections compared to the KB-TMF system.

Keywords: Double small buckling-retrained braces, Cumulative ductility, Hysteretic structure, Ductile truss moment frames, KB-TMF, STMF, Low yield strength.


Article Information


Identifiers and Pagination:

Year: 2019
Volume: 13
First Page: 10
Last Page: 19
Publisher Id: TOCIEJ-13-10
DOI: 10.2174/1874149501913010010

Article History:

Received Date: 05/12/2018
Revision Received Date: 01/01/2019
Acceptance Date: 14/01/2019
Electronic publication date: 28/02/2019
Collection year: 2019

Article Metrics:

CrossRef Citations:
0

Total Statistics:

Full-Text HTML Views: 411
Abstract HTML Views: 316
PDF Downloads: 231
ePub Downloads: 148
Total Views/Downloads: 1106

Unique Statistics:

Full-Text HTML Views: 248
Abstract HTML Views: 189
PDF Downloads: 157
ePub Downloads: 88
Total Views/Downloads: 682
Geographical View

© 2019 Sugihardjo et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: (https://creativecommons.org/licenses/by/4.0/legalcode). This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


* Address correspondence to this author at the Department of Civil Engineering, Institut Teknologi Sepuluh Nopember (ITS), Surabaya, Indonesia; Tel: 62315946096; E-mails: hidajat.sugihardjo@gmail.com and hidayat@ce.its.ac.id.




1. INTRODUCTION

Implementation of the Buckling-Restrained Brace (BRB) as a seismic absorption element or fuse in the high-rise steel structures had shown a significant development. The cross-section of the system consists of a core that has equal capacity for both compression and tension, and a sleeve that works to prevent the core from buckling. Watanabe et al. [1A. Watanabe, Y. Hitomi, E. Saeki, A. Wada, and M. Fujimoto, "Properties of brace encased buckling-restraining concrete and steel tube", 9thWorld Conference on Earthquake Engineering, vol. vol. IV, pp. 719-724.Tokyo-Kyoto, Japan] proposed a rectangular core embedded inside the unbonded materials which was found to be the first work in BRB system. As the BRB system further develops, steel with Low Yield strength (LY) is more preferred as the BRB core material. The strain of the LY steel material can extend up to three times of the A36 steel material. Furthermore, with lower yield strength than the A36 steel material, the BRB elements will yield at a lower seismic load, resulting in a marginal reduction of the overall structural stiffness. Hence, it is expected that the ductility of the structures increases [2K. Inoue, "Low yield-point steel for steel dampers", Steel Construction Today and Tomorrow., . the Japan Iron and Steel Federation-4T. Katayama, S. Ito, H. Kamura, T. Ueki, and H. Okamoto, "Experimental study on hysteretic damper with Low yield strength steel under dynamic loading", 12th World Conference on Earthquake Engineering, .].

Jia et al. [5M. Jia, D. Lu, L. Guo, and L. Sun, "Experimental research and cyclic behavior of buckling-restrained braced composite frame", J. Construct. Steel Res., no. 90, pp. 90-105.[http://dx.doi.org/10.1016/j.jcsr.2013.11.021] ] conducted an experimental test to study the behavior of BRB in a structural frame with composite steel-concrete column. From [5M. Jia, D. Lu, L. Guo, and L. Sun, "Experimental research and cyclic behavior of buckling-restrained braced composite frame", J. Construct. Steel Res., no. 90, pp. 90-105.[http://dx.doi.org/10.1016/j.jcsr.2013.11.021] ], it was found that the resulted energy dissipation and ductility of the structural frame with BRB system were higher than a conventional frame without BRB system. However, it was noted that the connection between the beam, column and bracing should be designed to avoid the connection failures. Fahnestock et al. [6L.A. Fahnestock, J.M. Ricles, and R. Sause, "Experimental evaluation of a large-scale BRBF", J. Struct. Eng., vol. 133, pp. 1205-1214.[http://dx.doi.org/10.1061/(ASCE)0733-9445(2007)133:9(1205)] ] performed some large-scale experimental tests of a frame with BRB system. From the test, the maximum drift ratio of the structures reached 5%. However, it should be noted that when the storey drift reached 2~2.5%, the structural performance was degraded due to the use of rigid beam-column-bracing connection. Qu et al. [7B. Qu, X. Liu, H. Hou, and C. Qiu, "Testing of buckling-restrained braces with replaceable steel angle fuses", J. Struct. Eng., vol. 144, no. 3, .[http://dx.doi.org/10.1061/(ASCE)ST.1943-541X.0001985] ] also conducted an experimental study and proposed a replaceable BRB system which was made of L-shape steel section. From the test, it was observed that the proposed BRB system had a stable hysteretic behavior at a fairly high strain. Other researchers also noted that the use of unbounded BRB system was found to be practical to increase the seismic resistance of the existing and new structures [8C.J. Black, N. Makris, and I.D. Aiken, "Component testing, seismic evaluation and characterization of buckling-restrained braces", J. Struct. Eng., vol. 130, no. 6, pp. 880-894.[http://dx.doi.org/10.1061/(ASCE)0733-9445(2004)130:6(880)] ]. Furthermore, with a proper placement of BRB element [9M. Ahmed, S. Tayyaba, and M. W. Ashraf, "Effect of buckling restrained braces locations on seismic responses of high-rise RC core wall buildings", Shock and Vibration, p. 15.[http://dx.doi.org/10.1155/2016/6808137] ], the use of BRB system can reduce the shear force in the shear wall reinforced concrete building. AISC code is usually used to design the BRB element. However, from the experimental test carried out by Chou et al. [10C.C. Chou, J. Liu, and D.H. Pham, "Steel buckling-restrained braced frames with single and dual corner gusset connections: Seismic test and analyses", Earthquake Eng. Struct. Dynam., vol. 41, pp. 1137-1156.[http://dx.doi.org/10.1002/eqe.1176] ], the AISC prediction of the buckling load of the BRB element [11American Institute of Steel Construction (AISC), Seismic Provisions for Structural Steel Buildings, ANSI/AISC 341-05: Chicago, Ill., USA, .] was higher than the test result.

Sugihardjo [12H. Sugihardjo, "Inelastic behaviour of ductile buckling-restrained braced truss-girders frames as component of storey buildings", (Ph.D. thesis), School of Postgraduate, Institute Teknologi Bandung: Bandung, Indonesia, ., 13H. Sugihardjo, "Earthquake-resistant building: Buckling-restrained braced truss-girder moment frames (Proposed)", IPTEK, J. Technol. Sci., vol. 19, no. 1, pp. 24-44.] carried out both experimental and numerical investigations of the SBRB system on the Buckling-Restrained Braced Truss Moment Frame (BRB-TMF). In some studies [12H. Sugihardjo, "Inelastic behaviour of ductile buckling-restrained braced truss-girders frames as component of storey buildings", (Ph.D. thesis), School of Postgraduate, Institute Teknologi Bandung: Bandung, Indonesia, ., 13H. Sugihardjo, "Earthquake-resistant building: Buckling-restrained braced truss-girder moment frames (Proposed)", IPTEK, J. Technol. Sci., vol. 19, no. 1, pp. 24-44.], the behavior of the BRB element was modelled using the bilinear stress-strain curve. From the analysis, it was found that the hysteresis curve of the BRB-TMF system showed a fairly stable behavior. However, the rigidity of the hysteresis curve degraded at a higher cycle mode. Nevertheless, the computed total hysteresis energy agrees well with the test result. Wongpakdee et al. [14N. Wongpakdee, S. Leelataviwat, S.C. Goel, and W.C. Liao, "Performance-based design and collapse evaluation of buckling restrained knee braced truss moment frames", Eng. Struct., vol. 60, pp. 23-31.[http://dx.doi.org/10.1016/j.engstruct.2013.12.014] ] proposed a Knee Braced Truss Moment Frame (KB-TMF) using SBRB system which was investigated analytically using the Performed-Based Plastic Design (PBPD). From the analysis, at the collapsed load, it was found that the KB-TMF system was able to be strained up to seven percent. Longo et al. [15A. Longo, R. Montuori, and V. Piluso, "Failure mode control and seismic response of dissipative truss moment frames", J. Struct. Eng., vol. 138, no. 11, pp. 1388-1397.[http://dx.doi.org/10.1061/(ASCE)ST.1943-541X.0000569] ] proposed a design procedure for the truss moment frames which ensures that the intended element (BRB) is yielded before the main structural elements.

Sugihardjo and Tavio [16H. Sugihardjo, and Tavio, "Cumulative ductility and hysteretic behavior of small buckling-restrained braces", Advances in Civil Engineering, vol. Vol. 2017, p. 11.] conducted an experimental test for the SBRB element with a rectangular core. In a study [16H. Sugihardjo, and Tavio, "Cumulative ductility and hysteretic behavior of small buckling-restrained braces", Advances in Civil Engineering, vol. Vol. 2017, p. 11.], the non-linear finite element analysis was performed using two constitutive laws for the steel material, the elasto-plastic bilinear and the Menegotto-Pinto stress-strain models. From the analysis, it was found that the experimental hysteresis curve is similar to that of the FE model with the steel material modelled using the Menegotto-Pinto stress-strain model. On the other hand, the use of elasto-plastic bilinear stress-strain model showed a compatible cumulative hysteresis energy compared to the test result. From the test result, the hysteresis curve shown a stable behavior up to two percent strain and the cumulative ductility of the SBRB element satisfied the requirements as the hysteresis element.

In this paper, a double SBRB system has been proposed as the ductile elements at both ends of the truss structures and is called as the Double Braced-Truss Moment Frames (DB-TMF). The proposed system is an extended development of the KB-TMF system. KB-TMF system only uses a single bracing [14N. Wongpakdee, S. Leelataviwat, S.C. Goel, and W.C. Liao, "Performance-based design and collapse evaluation of buckling restrained knee braced truss moment frames", Eng. Struct., vol. 60, pp. 23-31.[http://dx.doi.org/10.1016/j.engstruct.2013.12.014] ]. Since the SBRB position on the DB-TMF system may not conform architecturally, the DB-TMF system is only placed around the building perimeter. During the design process, the SBRB element is designed to yield first by increasing the strength of other truss elements with the over strength factor. This way, the other truss elements will remain elastic during the load excitation except for the connection between the chords and the columns [14N. Wongpakdee, S. Leelataviwat, S.C. Goel, and W.C. Liao, "Performance-based design and collapse evaluation of buckling restrained knee braced truss moment frames", Eng. Struct., vol. 60, pp. 23-31.[http://dx.doi.org/10.1016/j.engstruct.2013.12.014] ]. With the design procedure mentioned above, it is expected that the damage in the structural elements occurred in the SBRB elements and the chords adjacent to the columns which are acceptable.

2. MATERIALS AND METHODS

2.1. Conventional and Ductile Truss

Fig. (1) shows the development of conventional Truss Moment Frames (TMF) which has a non-ductile behavior Fig. (1) to a more advanced TMF system which focuses on the ductility and energy absorption of the structures. In the conventional truss system, the failure occurred at the compression diagonal strut, mainly due to buckling. Plastic hinge may also occur at the column. This type of TMF system does not satisfy the Strong Column Weak Beam design philosophy. Previous research also shows that the hysteresis curve is small and is not stable [17S.C. Goel, and A.M. Itani, "Seismic behavior of open web truss moment frames", J. Struct. Eng., vol. 120, no. 6, pp. 1763-1780.[http://dx.doi.org/10.1061/(ASCE)0733-9445(1994)120:6(1763)] ]. In Fig. (1), the structural system is called as the Special Truss Moment Frames (STMF). In the STMF system, the seismic energy absorption is carried out by the failure in X-bracing (yielding and buckling) and the plastic hinges that occurs at the ends of the ductile elements. The STMF structural system can be designed with a seismic reduction factor of seven [11American Institute of Steel Construction (AISC), Seismic Provisions for Structural Steel Buildings, ANSI/AISC 341-05: Chicago, Ill., USA, .] and the span can extend up to 12 m [18S.C. Goel, and A.M. Itani, "Seismic-resistant special truss-moment frames", J. Struct. Eng., vol. 120, no. 6, pp. 1781-1797.[http://dx.doi.org/10.1061/(ASCE)0733-9445(1994)120:6(1781)] ]. In Fig. (1), the truss system is the Vierendeel types. The Vierendeel structural system dissipates the seismic energy via the plastic hinges at both ends of the ductile elements. The advantage of this structural system is the availability of the unused room inside the structures that can be used for plumbing and utilities cables [19H.S. Basha, and S.C. Goel, "Seismic-resistant truss-moment frames with vierendeel segment", 11th World Conference on Earthquake Engineering, .]. Fig. (1) shows the BRB-TMF. This system changes the X-bracings with SBRBs [12H. Sugihardjo, "Inelastic behaviour of ductile buckling-restrained braced truss-girders frames as component of storey buildings", (Ph.D. thesis), School of Postgraduate, Institute Teknologi Bandung: Bandung, Indonesia, ., 13H. Sugihardjo, "Earthquake-resistant building: Buckling-restrained braced truss-girder moment frames (Proposed)", IPTEK, J. Technol. Sci., vol. 19, no. 1, pp. 24-44.]. Fig. (1) is the KB-TMF system where the energy dissipation is achieved via single SBRB and plastic hinges at the connection between the chords and columns [14N. Wongpakdee, S. Leelataviwat, S.C. Goel, and W.C. Liao, "Performance-based design and collapse evaluation of buckling restrained knee braced truss moment frames", Eng. Struct., vol. 60, pp. 23-31.[http://dx.doi.org/10.1016/j.engstruct.2013.12.014] ]. Fig. (1) shows the proposed DB-TMF, which uses two SBRB elements that are placed at both ends of the girder. The vertical and diagonal truss elements are connected to the chords using pin connection. The chords itself are designed as beam-column elements.

2.2. Analytical Model for Design and Non-Linear Investigation

To fulfill the main objective of this research, a DB-TMF system of four stories building with seven longitudinal spans is simulated. Fig. (2) shows the plan view and the longitudinal cross section of the buildings. The DB-TMF system is placed only at the perimeter of the building. It is expected that the DB-TMF system carries all seismic load while the rest of the structures only designed for gravity loads. For design purpose, SAP 2000 [20SAP2000, "Structural analysis program", version 14.2.2., Computers and Structures, Inc., .] is used to analyze and design the required steel section. A response spectrum analysis is used to simulate the applied seismic load to the structure during the design process. On the other hand, to study the inelastic behavior of the designed system, Non-Linear Time History Analysis (NL-THA) according to SNI 1726 [21SNI,1726, "Design regulations of earthquake resistant buildings and non buildings", Indonesian National Standard, .] is used. From the NL-THA, the performance of the proposed system can be examined and appropriate seismic load reduction factor (R) can be proposed.

Fig. (1)
Type of truss moment frames.


Fig. (2)
Analytical Model: (a). Plan; (b). Longitudinal elevation of DB-TMF.


Fig. (3)
Simplified analytical model of a half span structure: (a) DB-TMF; (b) KB-TMF.


Fig. (4)
Load pattern for drift ratio of frame systems.


To maintain equality in the comparisons, the magnitude of the seismic load is adjusted [18S.C. Goel, and A.M. Itani, "Seismic-resistant special truss-moment frames", J. Struct. Eng., vol. 120, no. 6, pp. 1781-1797.[http://dx.doi.org/10.1061/(ASCE)0733-9445(1994)120:6(1781)] ].

In Fig. (2), the outer left column is a cantilever column with equivalent stiffness of the interior columns in grid B plus C. This column is connected to the DB-TMF system using a rigid link to transfer the given seismic load to the DB-TMF system. SBRBs are placed at both ends of the beam. The inelastic capacity of the SBRBs element is set equal for both compressive and tensile forces. The columns and chords are modelled as a beam-column element while the vertical and diagonal elements are modelled as the plane truss. Once the designed steel section for each element is set as the final, NL-THA of the DB-TMF and nonlinear cyclic load analysis of the simplified TMF systems, as shown in Figs. (2 and 3), are carried out.

By examining the non-linear behavior of the TMF systems, it is possible to compute the cumulative ductility (η) of the structures. This cumulative ductility can be defined as the ratio of the total energy to the elastic energy. A structural system can be said to have the property of hysteresis structure if the value of η is greater than 20 [22H. Akiyama, "Earthquake-resistant limit-state design for building", University of Tokyo Press, 1985]. However, for the SBRB element, the value η must be greater than 100. From the test results [16H. Sugihardjo, and Tavio, "Cumulative ductility and hysteretic behavior of small buckling-restrained braces", Advances in Civil Engineering, vol. Vol. 2017, p. 11., 23H. Shimokawa, S. Ito, H. Kamura, S. Morino, and J. Kawaguchi, "Hysteretic behaviour of flat-bar stiffened by square steel tube", In: The Fifth Pacific Steel Structure Conference, Korea, 1998.], the value of η for the SBRB element is usually greater than 100.

Fig. (3) shows the simplified analytical models of the DB-TMF and KB-TMF systems which will be analyzed using the DRAIN-2DX finite element package [24D. Marinescu, and T. Benson, DRAIN-2DX, 64 bits version, University of California: Berkeley, California, USA, 2010.]. The non-linear behavior of the selected TMF system is carried out under cyclic load condition. It should be noted that due to symmetry, only a half span of the structure is modelled as shown in Fig. (3). In the analysis, both the SBRBs element and node A are allowed to yield [14N. Wongpakdee, S. Leelataviwat, S.C. Goel, and W.C. Liao, "Performance-based design and collapse evaluation of buckling restrained knee braced truss moment frames", Eng. Struct., vol. 60, pp. 23-31.[http://dx.doi.org/10.1016/j.engstruct.2013.12.014] ] while the rest of the elements will remain elastic.

In DRAIN-2DX, the inelastic plane truss element uses the TYPE01 elements while the inelastic beam-column element uses the TYPE02 elements. The TYPE01 element in DRAIN-2DX can undergo yielding in both compression and tension, as well as buckling in compression. The load in Fig. (3) is applied as displacement, based on which, it is computed as the drift ratio from 0.5 up to 3%. The load pattern of the cyclic load is shown in Fig. (4).

3. RESULTS AND DISCUSSION

3.1. Design of Section

The total ultimate dead plus live loads of the structure for each floor is 38.3 kN/m2 which was similar to the value reported in another study [18S.C. Goel, and A.M. Itani, "Seismic-resistant special truss-moment frames", J. Struct. Eng., vol. 120, no. 6, pp. 1781-1797.[http://dx.doi.org/10.1061/(ASCE)0733-9445(1994)120:6(1781)] ]. The values for the seismic reduction factor (R) and the importance factor (I) are set to 4.5 and 1.0, respectively. The assumption of using the value for R equal to 4.5 is to study whether the proposed system can at least satisfy the minimum requirements of ordinary truss moment frame system. The parameter of the designed spectral acceleration for short period SDS is set to 0.585 which is similar to the Surabaya city response spectrum with medium soil category. The base shear of the structures is computed as [21SNI,1726, "Design regulations of earthquake resistant buildings and non buildings", Indonesian National Standard, .]:

(1)

where W is the total weight of the structure.

By inserting the value of SDS, I and R into Eqn.(1), the total seismic base shear computed was 0.13W which was similar to [18S.C. Goel, and A.M. Itani, "Seismic-resistant special truss-moment frames", J. Struct. Eng., vol. 120, no. 6, pp. 1781-1797.[http://dx.doi.org/10.1061/(ASCE)0733-9445(1994)120:6(1781)] ]. All of the structural elements are designed using Bj41 steel material [25SNI,1729, "Design regulations of steel structures for buildings", Indonesian National Standard, .] where the yield strength is equal to the A36 steel material. The ratio of inelastic to elastic modulus is assumed to be around 3% [26M. Bruneau, C.M. Uang, and R. Sabelli, "Ductile Design of Steel Structures" 2nd ed McGraw-Hill:New York, USA, 2011]. By using the elastic analysis in SAP 2000 [14N. Wongpakdee, S. Leelataviwat, S.C. Goel, and W.C. Liao, "Performance-based design and collapse evaluation of buckling restrained knee braced truss moment frames", Eng. Struct., vol. 60, pp. 23-31.[http://dx.doi.org/10.1016/j.engstruct.2013.12.014] ] and the design code based on SNI 1729 [25SNI,1729, "Design regulations of steel structures for buildings", Indonesian National Standard, .], the steel section was designed, and the design results are shown in Table 1.

In Table 1, Columns (1) and (2) show the results of the designed steel section for the DB-TMF and KB-TMF system, respectively. It is worth mentioning that the effective length factor of the KB-TMF columns is larger than the DB-TMF columns. Hence, the designed section of the KB-TMF columns is also larger than the DB-TMF columns. The selection of the core SBRB section must satisfy the requirements of a compact section (b/t < 7.5, [23H. Shimokawa, S. Ito, H. Kamura, S. Morino, and J. Kawaguchi, "Hysteretic behaviour of flat-bar stiffened by square steel tube", In: The Fifth Pacific Steel Structure Conference, Korea, 1998.]). It is shown in Table 1 that the total weight of the KB-TMF system is 8.58 kN which has 19.8% higher weight compared to the proposed DB-TMF system. A rigid assumption between the chords and the column (point A in Fig. (3) was used in the above analysis.

To get the roof-top displacement, the model shown in Fig. (1) was further investigated using the NL-THA which was scaled based on the Surabaya city response spectrum. Fig. (5) shows the results of the scaled Time History response using the available software [27Seismo Signal, Earthquake Engineering Software Solutions, vol. 5.1.2, Seismosoft Ltd: Vat Italy, .]. The investigated time histories data were Miyagi (1978), Elcentro (1932), Northridge (1984) and Kobe (1985). Using the software [27Seismo Signal, Earthquake Engineering Software Solutions, vol. 5.1.2, Seismosoft Ltd: Vat Italy, .], the scale factors for each time histories obtained were 0.303, 0.727, 0.280 and 0.244 for Miyagi (1978), Elcentro (1932), Northridge (1984) and Kobe (1985) records, respectively.

Fig. (6) shows the drift ratios of the DB-TMF system with the selected time history data. In Fig. (6), Miyagi (1978) time history analysis gives the largest structural floor-to-floor displacement. This can be explained because the period of the structure is 1.03 second which is close to the peak acceleration response of the Miyagi time history data (Fig. 5). In Fig. (6), it can be seen that all the drift ratios of the proposed DB-TMF system are still lower than the code maximum threshold which is 2.0%.

Fig. (7) shows the roof-top displacement for each the carried-out NL-THA. The response of the DB-TMF system is asymptotic which differs from the conventional truss system. In the conventional truss system, the roof-top displacement moves away from the horizontal axis due to excessive unequal yielding in the elements [17S.C. Goel, and A.M. Itani, "Seismic behavior of open web truss moment frames", J. Struct. Eng., vol. 120, no. 6, pp. 1763-1780.[http://dx.doi.org/10.1061/(ASCE)0733-9445(1994)120:6(1763)] ].

3.2. Analysis of the Proposed DB-TMF System as a STMF

This section investigates the performance of the proposed model when designed as a STMF with R = 7. Response spectrum analysis with the design spectral response acceleration (SDS) equal to 0.9 (Aceh city) is applied to the structure. The steel sections were designed accordingly which resulted in the DB-TMF-1 system configuration as shown in Table 1 (column 3). As shown in Table 1, all the structural elements of the DB-TMF-1 system had all the section size increased (except the vertical and diagonal trusses) to fulfill the requirement of the STMF system. Using a similar analysis and software [27Seismo Signal, Earthquake Engineering Software Solutions, vol. 5.1.2, Seismosoft Ltd: Vat Italy, .] in the previous section, the data of time histories were scaled again with respect to Aceh city response spectrum (SDS = 0.9) which gave the scaling parameters for Miyagi, Elcentro, Northridge and Kobe time histories data equal to 0.520, 1.225, 0.478 and 0.415, respectively.

Fig. (8) shows the drift ratios of the proposed DB-TMF-1 system and the other TMF systems with Miyagi time history data. The drift ratio of the proposed DB-TMF-1 system showed a significant reduction compared to the other system such as BRB-TMF [12H. Sugihardjo, "Inelastic behaviour of ductile buckling-restrained braced truss-girders frames as component of storey buildings", (Ph.D. thesis), School of Postgraduate, Institute Teknologi Bandung: Bandung, Indonesia, .], conventional truss, solid frames, Vierendeel and STMF [18S.C. Goel, and A.M. Itani, "Seismic-resistant special truss-moment frames", J. Struct. Eng., vol. 120, no. 6, pp. 1781-1797.[http://dx.doi.org/10.1061/(ASCE)0733-9445(1994)120:6(1781)] ]. The rooftop displacement behavior of the DB-TMF-1 using the NL-THA with the selected time histories data is shown in Fig. (9). In Fig. (9), there are two earthquakes which restricted the proposed system to achieve the asymptotic behavior and move away from the abscissa. This indicates that the proposed system is not suitable to be used in high-seismic zone despite the smaller drift ratio compared to other STMF system.

3.3. Hysteresis Curve of the DB-TMF

To find out how much energy that can be absorbed by the structural system, in Fig. (3), a displacement cyclic loading pattern is given at the top of the column. The cyclic loading pattern is a function of the drift ratio as shown in Fig. (4) [12H. Sugihardjo, "Inelastic behaviour of ductile buckling-restrained braced truss-girders frames as component of storey buildings", (Ph.D. thesis), School of Postgraduate, Institute Teknologi Bandung: Bandung, Indonesia, ., 13H. Sugihardjo, "Earthquake-resistant building: Buckling-restrained braced truss-girder moment frames (Proposed)", IPTEK, J. Technol. Sci., vol. 19, no. 1, pp. 24-44., 18S.C. Goel, and A.M. Itani, "Seismic-resistant special truss-moment frames", J. Struct. Eng., vol. 120, no. 6, pp. 1781-1797.[http://dx.doi.org/10.1061/(ASCE)0733-9445(1994)120:6(1781)] ]. Fig. (10) shows the hysteresis curve for the DB-TMF system. In Fig. (10), the behavior of the hysteresis curve is pinching, and the stiffness of the system is degraded during reverse loading phase.

The hysteresis curve for the bottom and upper-bracing can be seen in Fig. (10). This figure shows that the maximum axial deformation for the bottom and upper-SBRB reaches 36.88 mm (at axial strain about 2.32%) and 18.55 mm (at axial strain about 1.17%), respectively. The top bracing absorbed lower cyclic load energy which was the primary cause of the stiffness degradation of the DB-TMF system during the reverse loading phase (Fig. 10). Both bracings were not fully functional as the buckling restrained braces because there were no shortening strains in the cyclic responses.

Table 1
Sections of DB-TMF and KB-TMF.


Fig. (5)
Scaling of the time history records to Surabaya city response spectrum.


Fig. (6)
Drift ratios of the DB-TMF system with various time history data for R=4.5.


Fig. (7)
Roof-top displacement for various records, with R=4.5.


Fig. (8)
Drift ratios due to Miyagi time history data with R=7 for various types of moment frames.


Fig. (9)
Roof-top displacement for various records, with R=7.


3.4. Evaluation of the Hysteresis Curve of the KB-TMF

In a study [14N. Wongpakdee, S. Leelataviwat, S.C. Goel, and W.C. Liao, "Performance-based design and collapse evaluation of buckling restrained knee braced truss moment frames", Eng. Struct., vol. 60, pp. 23-31.[http://dx.doi.org/10.1016/j.engstruct.2013.12.014] ], the performance of the KB-TMF under cyclic load was not determined and it is one of the authors’ interests to evaluate the hysteresis behavior of the KB-TMF [14N. Wongpakdee, S. Leelataviwat, S.C. Goel, and W.C. Liao, "Performance-based design and collapse evaluation of buckling restrained knee braced truss moment frames", Eng. Struct., vol. 60, pp. 23-31.[http://dx.doi.org/10.1016/j.engstruct.2013.12.014] ] under cyclic loads.

Therefore, in this section, the KB-TMF system is also investigated the same way as DB-TMF system. Fig. (11) and Fig. (11) shows the hysteresis curves for the KB-TMF and single SBRB systems, respectively. Fig. (11) shows that the performance of the KB-TMF system with single bracing is not optimal in carrying cyclic loading. There exists pinching when the load changes from push to pull direction. During the cyclic load excitation, plastic hinge in node A occurred. This finding also agrees well with another research carried out [14N. Wongpakdee, S. Leelataviwat, S.C. Goel, and W.C. Liao, "Performance-based design and collapse evaluation of buckling restrained knee braced truss moment frames", Eng. Struct., vol. 60, pp. 23-31.[http://dx.doi.org/10.1016/j.engstruct.2013.12.014] ]. On the other hand, in the analysis shown in Fig. (11), the performance of single SBRB system is similar with the double SBRB elements (bracing 70 × 10 mm) in DB-TMF systems.

3.5. Hysteresis Energy and Cumulative Ductility

Table 2 shows the hysteresis energy and the cumulative ductility factor η. From Figs. (10 and 11), the cumulative ductility can be calculated. The DB-TMF system has the cumulative ductility of 31.5 greater than the KB-TMF system (η = 27.1, see column (4) in Table 2). This indicates that the DB-TMF system has better hysteresis behavior compared to the KB-TMF system. Both the DB-TMF and KB-TMF systems have a value of η greater than 20 which, in all the systems, satisfies the requirements as a hysteresis structure.

In column (5), for the DB-TMF system, a residual energy of about 12,790 kN-mm (44% of the total energy) is shown which was absorbed by the plastic hinge as a consequence of using the fixed assumption in node A. In the KB-TMF system, the energy absorbed in the plastic hinge was around 11,678 kN-mm (40% of the total energy). This further indicates that node A for both the DB-TMF and KB-TMF systems had relatively large plastic rotation. The bracings for both systems absorbed about 60% of the total energy. From column (4) in Table 2, it can be seen that the value for the cumulative ductility for all type of bracings is still lower than 100. This value of η was observed to be much smaller than the test results which ranged from 199~450 [16H. Sugihardjo, and Tavio, "Cumulative ductility and hysteretic behavior of small buckling-restrained braces", Advances in Civil Engineering, vol. Vol. 2017, p. 11.].

Fig. (10)
Hysteresis curves: a). DB-TMF; b). Bottom and upper SBRBs.


Table 2
Hysteresis energy and cumulative ductility factor (η).


Fig. (11)
Hysteresis curves: a). KB-TMF; b). single SBRB.


CONCLUSION

This paper proposed a Small Buckling-Restrained Brace (SBRB) for the Double Braced-Truss-Moment Resisting Frames (DB-TMF). SAP 2000 finite element package was used to analyze and design the steel section of four stories building. The seismic load used in design was based on the response spectrum analysis. NL-THA was used to study the behavior of the roof-top displacement and the drift ratio of the structure. On the other hand, DRAIN-2DX finite element computer package was used to study the DB-TMF and KB-TMF system under cyclic load. Using the DB-TMF system as the ordinary truss moment frames, the drift ratio with varying time history data shows the drift ratios to be lower than 2% thereby satisfying the code requirements. Compared to the KB-TMF system, the proposed DB-TMF system requires less steel material but has better hysteretic performance. The roof-top displacement of the DB-TMF system which was analyzed in DRAIN-2DX package with several earthquake time histories had shown an asymptotic behavior. The hysteresis curve was shown to be stable with excellent energy absorption which indicates that the proposed structural system (DB-TMF) can absorb moderate seismic load without a significant reduction in its stiffness. It is also worth mentioning that after the seismic excitation, the structural deformation is almost as in the original undeformed state. The elements that yields were the braces and the chords adjacent to the columns while other elements remained elastic. The performance of the DB-TMF system is still lower than other TMF systems such as STMF, Vierendeel and BRB-TMF. Therefore, the proposed DB-TMF system can be categorized as the Ordinary Truss Moment Frames with the value of R equal to 4.5 and can be used as an alternative structural system.

CONSENT FOR PUBLICATION

Not applicable.

CONFLICT OF INTEREST

The authors declare no conflict of interest, financial or otherwise.

ACKNOWLEDGEMENTS

Declared none.

REFERENCES

[1] A. Watanabe, Y. Hitomi, E. Saeki, A. Wada, and M. Fujimoto, "Properties of brace encased buckling-restraining concrete and steel tube", 9thWorld Conference on Earthquake Engineering, vol. vol. IV, pp. 719-724.Tokyo-Kyoto, Japan
[2] K. Inoue, "Low yield-point steel for steel dampers", Steel Construction Today and Tomorrow., . the Japan Iron and Steel Federation
[3] M. Nakashima, "Strain hardening behavior of shear panels made of low yield steel - I: Test", J. Struct. Eng., vol. 121, no. 12, pp. 1742-1749.[http://dx.doi.org/10.1061/(ASCE)0733-9445(1995)121:12(1742)]
[4] T. Katayama, S. Ito, H. Kamura, T. Ueki, and H. Okamoto, "Experimental study on hysteretic damper with Low yield strength steel under dynamic loading", 12th World Conference on Earthquake Engineering, .
[5] M. Jia, D. Lu, L. Guo, and L. Sun, "Experimental research and cyclic behavior of buckling-restrained braced composite frame", J. Construct. Steel Res., no. 90, pp. 90-105.[http://dx.doi.org/10.1016/j.jcsr.2013.11.021]
[6] L.A. Fahnestock, J.M. Ricles, and R. Sause, "Experimental evaluation of a large-scale BRBF", J. Struct. Eng., vol. 133, pp. 1205-1214.[http://dx.doi.org/10.1061/(ASCE)0733-9445(2007)133:9(1205)]
[7] B. Qu, X. Liu, H. Hou, and C. Qiu, "Testing of buckling-restrained braces with replaceable steel angle fuses", J. Struct. Eng., vol. 144, no. 3, .[http://dx.doi.org/10.1061/(ASCE)ST.1943-541X.0001985]
[8] C.J. Black, N. Makris, and I.D. Aiken, "Component testing, seismic evaluation and characterization of buckling-restrained braces", J. Struct. Eng., vol. 130, no. 6, pp. 880-894.[http://dx.doi.org/10.1061/(ASCE)0733-9445(2004)130:6(880)]
[9] M. Ahmed, S. Tayyaba, and M. W. Ashraf, "Effect of buckling restrained braces locations on seismic responses of high-rise RC core wall buildings", Shock and Vibration, p. 15.[http://dx.doi.org/10.1155/2016/6808137]
[10] C.C. Chou, J. Liu, and D.H. Pham, "Steel buckling-restrained braced frames with single and dual corner gusset connections: Seismic test and analyses", Earthquake Eng. Struct. Dynam., vol. 41, pp. 1137-1156.[http://dx.doi.org/10.1002/eqe.1176]
[11] American Institute of Steel Construction (AISC), Seismic Provisions for Structural Steel Buildings, ANSI/AISC 341-05: Chicago, Ill., USA, .
[12] H. Sugihardjo, "Inelastic behaviour of ductile buckling-restrained braced truss-girders frames as component of storey buildings", (Ph.D. thesis), School of Postgraduate, Institute Teknologi Bandung: Bandung, Indonesia, .
[13] H. Sugihardjo, "Earthquake-resistant building: Buckling-restrained braced truss-girder moment frames (Proposed)", IPTEK, J. Technol. Sci., vol. 19, no. 1, pp. 24-44.
[14] N. Wongpakdee, S. Leelataviwat, S.C. Goel, and W.C. Liao, "Performance-based design and collapse evaluation of buckling restrained knee braced truss moment frames", Eng. Struct., vol. 60, pp. 23-31.[http://dx.doi.org/10.1016/j.engstruct.2013.12.014]
[15] A. Longo, R. Montuori, and V. Piluso, "Failure mode control and seismic response of dissipative truss moment frames", J. Struct. Eng., vol. 138, no. 11, pp. 1388-1397.[http://dx.doi.org/10.1061/(ASCE)ST.1943-541X.0000569]
[16] H. Sugihardjo, and Tavio, "Cumulative ductility and hysteretic behavior of small buckling-restrained braces", Advances in Civil Engineering, vol. Vol. 2017, p. 11.
[17] S.C. Goel, and A.M. Itani, "Seismic behavior of open web truss moment frames", J. Struct. Eng., vol. 120, no. 6, pp. 1763-1780.[http://dx.doi.org/10.1061/(ASCE)0733-9445(1994)120:6(1763)]
[18] S.C. Goel, and A.M. Itani, "Seismic-resistant special truss-moment frames", J. Struct. Eng., vol. 120, no. 6, pp. 1781-1797.[http://dx.doi.org/10.1061/(ASCE)0733-9445(1994)120:6(1781)]
[19] H.S. Basha, and S.C. Goel, "Seismic-resistant truss-moment frames with vierendeel segment", 11th World Conference on Earthquake Engineering, .
[20] SAP2000, "Structural analysis program", version 14.2.2., Computers and Structures, Inc., .
[21] SNI,1726, "Design regulations of earthquake resistant buildings and non buildings", Indonesian National Standard, .
[22] H. Akiyama, "Earthquake-resistant limit-state design for building", University of Tokyo Press, 1985
[23] H. Shimokawa, S. Ito, H. Kamura, S. Morino, and J. Kawaguchi, "Hysteretic behaviour of flat-bar stiffened by square steel tube", In: The Fifth Pacific Steel Structure Conference, Korea, 1998.
[24] D. Marinescu, and T. Benson, DRAIN-2DX, 64 bits version, University of California: Berkeley, California, USA, 2010.
[25] SNI,1729, "Design regulations of steel structures for buildings", Indonesian National Standard, .
[26] M. Bruneau, C.M. Uang, and R. Sabelli, "Ductile Design of Steel Structures" 2nd ed McGraw-Hill:New York, USA, 2011
[27] Seismo Signal, Earthquake Engineering Software Solutions, vol. 5.1.2, Seismosoft Ltd: Vat Italy, .

Endorsements



"Open access will revolutionize 21st century knowledge work and accelerate the diffusion of ideas and evidence that support just in time learning and the evolution of thinking in a number of disciplines."


Daniel Pesut
(Indiana University School of Nursing, USA)

"It is important that students and researchers from all over the world can have easy access to relevant, high-standard and timely scientific information. This is exactly what Open Access Journals provide and this is the reason why I support this endeavor."


Jacques Descotes
(Centre Antipoison-Centre de Pharmacovigilance, France)

"Publishing research articles is the key for future scientific progress. Open Access publishing is therefore of utmost importance for wider dissemination of information, and will help serving the best interest of the scientific community."


Patrice Talaga
(UCB S.A., Belgium)

"Open access journals are a novel concept in the medical literature. They offer accessible information to a wide variety of individuals, including physicians, medical students, clinical investigators, and the general public. They are an outstanding source of medical and scientific information."


Jeffrey M. Weinberg
(St. Luke's-Roosevelt Hospital Center, USA)

"Open access journals are extremely useful for graduate students, investigators and all other interested persons to read important scientific articles and subscribe scientific journals. Indeed, the research articles span a wide range of area and of high quality. This is specially a must for researchers belonging to institutions with limited library facility and funding to subscribe scientific journals."


Debomoy K. Lahiri
(Indiana University School of Medicine, USA)

"Open access journals represent a major break-through in publishing. They provide easy access to the latest research on a wide variety of issues. Relevant and timely articles are made available in a fraction of the time taken by more conventional publishers. Articles are of uniformly high quality and written by the world's leading authorities."


Robert Looney
(Naval Postgraduate School, USA)

"Open access journals have transformed the way scientific data is published and disseminated: particularly, whilst ensuring a high quality standard and transparency in the editorial process, they have increased the access to the scientific literature by those researchers that have limited library support or that are working on small budgets."


Richard Reithinger
(Westat, USA)

"Not only do open access journals greatly improve the access to high quality information for scientists in the developing world, it also provides extra exposure for our papers."


J. Ferwerda
(University of Oxford, UK)

"Open Access 'Chemistry' Journals allow the dissemination of knowledge at your finger tips without paying for the scientific content."


Sean L. Kitson
(Almac Sciences, Northern Ireland)

"In principle, all scientific journals should have open access, as should be science itself. Open access journals are very helpful for students, researchers and the general public including people from institutions which do not have library or cannot afford to subscribe scientific journals. The articles are high standard and cover a wide area."


Hubert Wolterbeek
(Delft University of Technology, The Netherlands)

"The widest possible diffusion of information is critical for the advancement of science. In this perspective, open access journals are instrumental in fostering researches and achievements."


Alessandro Laviano
(Sapienza - University of Rome, Italy)

"Open access journals are very useful for all scientists as they can have quick information in the different fields of science."


Philippe Hernigou
(Paris University, France)

"There are many scientists who can not afford the rather expensive subscriptions to scientific journals. Open access journals offer a good alternative for free access to good quality scientific information."


Fidel Toldrá
(Instituto de Agroquimica y Tecnologia de Alimentos, Spain)

"Open access journals have become a fundamental tool for students, researchers, patients and the general public. Many people from institutions which do not have library or cannot afford to subscribe scientific journals benefit of them on a daily basis. The articles are among the best and cover most scientific areas."


M. Bendandi
(University Clinic of Navarre, Spain)

"These journals provide researchers with a platform for rapid, open access scientific communication. The articles are of high quality and broad scope."


Peter Chiba
(University of Vienna, Austria)

"Open access journals are probably one of the most important contributions to promote and diffuse science worldwide."


Jaime Sampaio
(University of Trás-os-Montes e Alto Douro, Portugal)

"Open access journals make up a new and rather revolutionary way to scientific publication. This option opens several quite interesting possibilities to disseminate openly and freely new knowledge and even to facilitate interpersonal communication among scientists."


Eduardo A. Castro
(INIFTA, Argentina)

"Open access journals are freely available online throughout the world, for you to read, download, copy, distribute, and use. The articles published in the open access journals are high quality and cover a wide range of fields."


Kenji Hashimoto
(Chiba University, Japan)

"Open Access journals offer an innovative and efficient way of publication for academics and professionals in a wide range of disciplines. The papers published are of high quality after rigorous peer review and they are Indexed in: major international databases. I read Open Access journals to keep abreast of the recent development in my field of study."


Daniel Shek
(Chinese University of Hong Kong, Hong Kong)

"It is a modern trend for publishers to establish open access journals. Researchers, faculty members, and students will be greatly benefited by the new journals of Bentham Science Publishers Ltd. in this category."


Jih Ru Hwu
(National Central University, Taiwan)


Browse Contents



Webmaster Contact: info@benthamopen.net
Copyright © 2019 Bentham Open