In Europe, concentrically braced frames (CBFs) with double angle bracings are the most frequent lateral-resistant structural systems. Although their standard bolted connections provide economic and robust solutions for the static loading, they are assumed to have almost zero ductility under strong earthquake actions. In order to avoid a brittle failure, the current seismic design requirements of European Code provisions require these joints to have sufficient over-strength, and to remain elastic for the design earthquake. While this is a safe approach for the high seismicity situations, it causes costly solutions for the buildings designed in the low-to-moderate seismicity context. Therefore, mainly for economy reasons, design engineers usually choose standard non-seismic approach (DCL) for the design of CBFs located in low-to-moderate seismic regions. However, such a choice may lead to unsafe solutions, since no effort is paid to control ductility. To combine safety and economy in this context, a new specific method has been studied in the recently concluded EU-RFCS MEAKADO project. To explore the inherent ductility provided by standard double-angle bracing joints with preloaded bolts and respecting new edge-spacing requirements, full scale tests have been performed as a project task. This article analyses the test results, and quantifies the ductility provided by the bolt hole ovalization and the slippage of preloaded bolts of the bracing joints not fulfilling the current over-strength design criteria. The test data has been analysed by means of LVDTs, strain gauges and thermal images. Such ductility and dissipation resources are traditionally not desired from a high seismicity design point of view, but may satisfy the low horizontal shear demand of the buildings designed for the low-to-moderate earthquake zones.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Tax calculation will be finalised during checkout.
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
Tax calculation will be finalised during checkout.
Astaneh-Asl A, Goel SC (1985) Cyclic in-plane buckling of double angle bracing. J Struct Eng 110:2036–2055
Ballio G, Perotti F (1987) Cyclic behaviour of axially loaded members: numerical simulation and experimental verification. J Constr Steel Res 7:3–41
Ballio G, Castiglioni CA, Perotti F (1988) Numerical models for simulating the cyclic behavior and the seismic response of steel structures. In: Proceedings of the ninth world conference on earthquake engineering, pp 231–236
Broderick BM, Elghazouli AY, Goggins J (2008) Earthquake testing and response analysis of concentrically-braced sub-frames. J Constr Steel Res 64:997–1007. doi:10.1016/j.jcsr.2007.12.014
Callister JP (2011) Seismic evaluation of an existing low ductility braced frame building in California. In: Structures congress, pp 2756–2767
Davaran A, Tremblay R, Beland T, Fahnestock LA, Hines EM (2014) Experimental behavior of low-ductility brace connection limit states. In: Proceedings of the Structures Congress, pp 2429–2441
Degee H et al (2013) Design of steel and composite structures with limited ductility requirements for optimized performances in moderate earthquake areas. MEAKADO Research Proposal for EU-RFCS
Degée H, Castiglioni C, Kanyilmaz A, Calderon I, Martin PO (2016) Design of concentrically braced steel frames for optimized performances in moderate earthquake areas. In: Proceedings of the international colloquium on stability and ductility of steel structures, SDSS 2016, pp 759–766
Degee H, Henriques JG, Vleminckx L, Denoel V, Wieschollek M, Hoffmeister B et al (2017) Design of steel and composite structures with limited ductility requirements for optimized performances in moderate earthquake areas. Final report of the research project MEAKADO, funded by Research Fund for Coal and Steel
ECCS no.45 (1986) Recommended testing procedure for assessing the behaviour of structural steel elements under cyclic loads
EN 1993-1-1 (2005) Eurocode 3: Design of steel structures - Part 1-1: General rules and rules for buildings
EN 1993-1-8 (2005) Eurocode 3: Design of steel structures - Part 1-8: Design of joints
EN 1998-1 (2004) Eurocode 8: Design of structures for earthquake resistance – Part 1: General rules, seismic actions and rules for buildings
Gioncu V, Mazzolani F (2010) Seismic design of steel structures. CRC Press, Boca Raton
Goggins J, Sullivan T (2009) Displacement-based seismic design of SDOF concentrically braced frames, pp 685–691
Han S-W, Choi Y-S (2008) Seismic hazard analysis in low and moderate seismic region-Korean peninsula. Struct Saf 30:543–558. doi:10.1016/j.strusafe.2007.10.004
IRSoft thermography software, version 3.3, Testo AG 2010
Kanyilmaz A (2016) Secondary frame action in concentrically braced frames designed for moderate seismicity: a full scale experimental study. Bull Earthq Eng 15:2101–2127. doi:10.1007/s10518-016-0054-x
Kanyilmaz A (2017) Role of compression diagonals in concentrically braced frames in moderate seismicity: A full scale experimental study. J Constr Steel Res 133:1–18. doi:10.1016/j.jcsr.2017.01.023
Kanyilmaz A, Castiglioni CA, Degèe H, Martin P (2015) A preliminary assessment of slenderness and over-strength homogenity criteria used in the design of concentrically braced steel frames in moderate seismicity. In: COMPDYN 2015—5th ECCOMAS thematic conference on computational methods in structural dynamics and earthquake engineering pp 3599–609
Kelly DJ, Zona JJ (2006) Design tips for steel in low or moderate seismicity regions. NASCC: The Steel Conference, Modern Steel Construction, February 2006
Kulak GL, Fisher JW, Struik JHA (1988) Guide to design criteria for bolted and riveted joints. Can J Civ Eng. doi:10.1139/l88-018
Landolfo R (2013) Assessment of EC8 provisions for seismic design of steel structures. ECCS TC13
Lumpkin EJ, Hsiao PC, Roeder CW, Lehman DE, Tsai CY, Wu AC et al (2012) Investigation of the seismic response of three-story special concentrically braced frames. J Constr Steel Res 77:131–144. doi:10.1016/j.jcsr.2012.04.003
Mayer Rosa D (1993) Towards uniform earthquake hazard assessment. Anal Di Geofis XXXVI:93–102
Merczel DB, Somja H, Aribert JM, Lógó J (2013) On the behaviour of concentrically braced frames subjected to seismic loading. Period Polytech Civ Eng 57:113–122. doi:10.3311/PPci.7167
Murty CVR, Malik JN (2008) Challenges of low-to-moderate seismicity in India. Electron J Struct Eng 77–87
Nelson TA, Gryniuk MC, Hines EM (2006) Comparison of low-ductility moment resisting frames and chevron braced frames under moderate seismic demands. In: 8th US national conference on earthquake engineering, vol 3, pp 1334–1343
Nordenson GJP, Bell GR (2000) Seismic design requirements for regions of moderate seismicity. Earthq Spectra 16:205–225
Pinto PE (2000) Design for low/moderate seismic risk. Bull N Z Soc Earthq Eng 33:303–324
Reaveley LD, Nordenson GJ (1990) Acceptable damage in low and moderate seismic zones. In: Fourth US-Japan workshop on the improvement of building structural design practices, Hawaii
Roeder CW, Lumpkin EJ, Lehman DE (2011) A balanced design procedure for special concentrically braced frame connections. J Constr Steel Res 67:1760–1772. doi:10.1016/j.jcsr.2011.04.016
Sen AD, Asce SM, Sloat D, Ballard R, Johnson MM, Roeder CW et al (2016) Experimental evaluation of the seismic vulnerability of braces and connections in older concentrically braced frames 142:1–15. doi:10.1061/(ASCE)ST.1943-541X.0001507
Stoakes CD (2012) Beam-column connection flexural behavior and seismic collapse performance of concentrically braced frames. PhD thesis, University of Illinois at Urbana-Champaign
Tremblay R (2002) Inelastic seismic response of steel bracing members. J Constr Steel Res 58:665–701. doi:10.1016/S0143-974X(01)00104-3
UNI EN 1090-2 (2011) UNI EN 1090-2 Execution of steel structures and aluminium structures part 2: technical requirements for steel structures
Uriz P, Mahin S (2008) Toward earthquake-resistant design of concentrically braced steel-frame structures, PEER Report 2008/08 pacific earthquake engineering research center college of engineering university of California, Berkeley
Wakabayashi M, Nakamura T, Yoshida N (1977) Experimental studies on the elastic-plastic behaviour of braced frames under repeated horizontal loading. Part 1 experiments of braces with an H-shaped cross section in a frame. Bull Disaster Prev Res Inst 27:121–154. doi:10.1017/CBO9781107415324.004
This article presents the results of full scale tests performed within MEAKADO project coordinated by Prof. Herve Degee, carried out with the financial grant of the Research Program of the Research Fund for Coal and Steel of the European Commission (RFSR-CT-2013-00022). Special thanks to Prof. Carlo Andrea Castiglioni, for his precious comments. Thanks to the manager and technicians of the LPM laboratories of Politecnico di Milano. Marco Cucchi from LPM Politecnico di Milano is also acknowledged for his help in performing thermal camera measurements and the analysis. Assistance from Master thesis students Alberto Volonterio and Umberto Rico during the test implementations is also deeply appreciated.
About this article
Cite this article
Kanyilmaz, A. Moderate ductility of the bracing joints with preloaded bolts. Bull Earthquake Eng 16, 503–527 (2018). https://doi.org/10.1007/s10518-017-0208-5
- Concentrically braced frames
- Moderate seismicity
- Joint ductility
- Double angle bracings
- Slip resistant joints
- Preloaded connections
- Bolted bracing connections
- Full scale tests