• Title/Summary/Keyword: seismic composite connection

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Bolted end plate connections for steel reinforced concrete composite structures

  • Li, Xian;Wu, Yuntian;Mao, Weifeng;Xiao, Yan;Anderson, J.C.;Guo, Yurong
    • Structural Engineering and Mechanics
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    • v.24 no.3
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    • pp.291-306
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    • 2006
  • In order to improve the constructability and meanwhile ensure excellent seismic behavior, several innovative composite connection details were conceived and studied by the authors. This paper reports experimental results and observations on seismic behavior of steel beam bolted to reinforced concrete column connections (bolted RCS or BRCS). The proposed composite connection details involve post tensioning the end plates of the steel beams to the reinforced concrete or precast concrete columns using high-strength steel rods. A rational design procedure was proposed to assure a ductile behavior of the composite structure. Strut-and-tie model analysis indicates that a bolted composite connection has a favorable stress transfer mechanism. The excellent capacity and behavior were then validated through five full-scale beam to column connection model tests.

Seismic Performance of Prefabricated Composite Column for Accelerated Bridge Construction (급속시공을 위한 조립식 합성교각의 내진성능 평가)

  • Lee, Jung-Woo;Chin, Won-Jong;Joh, Chang-Bin;Kwark, Jong-Won
    • Journal of the Korean Society for Railway
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    • v.13 no.4
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    • pp.425-430
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    • 2010
  • This paper investigates the seismic behavior of a prefabricated composite column which is made by onsite connection of precast composite column segments to accelerate bridge construction. Quasi-static cyclic loading tests were performed on three prefabricated composite columns with different connection details to find their seismic capacity. Test results show that the onsite connections remains in elastic range and no slip is observed as designed in spite of plastic hinge formation at the column. The test results also indicate that the prefabricated composite column has better overall seismic capacity compared to a conventional reinforced concrete column with seismic details.

Parametric study on probabilistic local seismic demand of IBBC connection using finite element reliability method

  • Taherinasab, Mohammad;Aghakouchak, Ali A.
    • Steel and Composite Structures
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    • v.37 no.2
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    • pp.151-173
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    • 2020
  • This paper aims to probabilistically evaluate performance of two types of I beam to box column (IBBC) connection. With the objective of considering the variability of seismic loading demand, statistical features of the inter-story drift ratio corresponding to the second, fifth and eleventh story of a 12-story steel special moment resisting frames are extracted through incremental dynamic analysis at global collapse state. Variability of geometrical variables and material strength are also taken into account. All of these random variables are exported as inputs to a probabilistic finite element model which simulates the connection. At the end, cumulative distribution functions of local seismic demand for each component of each connection are provided using histogram sampling. Through a parametric study on probabilistic local seismic demand, the influence of some geometrical random variables on the performance of IBBC connections is demonstrated. Furthermore, the probabilistic study revealed that IBBC connection with widened flange has a better performance than the un-widened flange. Also, a design procedure is proposed for WF connections to achieve a same connection performance in different stories.

Studies on restoring force model of concrete filled steel tubular laced column to composite box-beam connections

  • Huang, Zhi;Jiang, Li-Zhong;Zhou, Wang-Bao;Chen, Shan
    • Steel and Composite Structures
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    • v.22 no.6
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    • pp.1217-1238
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    • 2016
  • Mega composite structure systems have been widely used in high rise buildings in China. Compared to other structures, this type of composite structure systems has a larger cross-section with less weight. Concrete filled steel tubular (CFST) laced column to box-beam connections are gaining popularity, in particular for the mega composite structure system in high rise buildings. To enable a better understanding of the destruction characteristics and aseismic performance of these connections, three different connection types of specimens including single-limb bracing, cross bracing and diaphragms for core area of connections were tested under low cyclic and reciprocating loading. Hysteresis curves and skeleton curves were obtained from cyclic loading tests under axial loading. Based on these tested curves, a new trilinear hysteretic restoring force model considering rigidity degradation is proposed for CFST laced column to box-beam connections in a mega composite structure system, including a trilinear skeleton model based on calculation, law of stiffness degradation and hysteresis rules. The trilinear hysteretic restoring force model is compared with the experimental results. The experimental data shows that the new hysteretic restoring force model tallies with the test curves well and can be referenced for elastic-plastic seismic analysis of CFST laced column to composite box-beam connection in a mega composite structure system.

Modelling of flange-stud-slab interactions and numerical study on bottom-flange-bolted composite-beam connections

  • Xiaoxiang Wang;Yujie Yu;Lizhong Jiang;Zhiwu Yu
    • Steel and Composite Structures
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    • v.47 no.2
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    • pp.203-216
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    • 2023
  • The composite beam connections often encountered fracture failure in the welded bottom flange joint, and a bottom flange bolted connection has been proposed to increase the deformation ability of the bottom flange joint. The seismic performance of the bottom flange bolted composite beam connection was suffered from both the composite action of concrete slab and the asymmetric load transfer mechanisms between top and bottom beam flange joints. Thus, this paper presents a comprehensive numerical study on the working mechanism of the bottom flange bolted composite beam connections. Three available modelling methods and a new modelling method on the flange-stud-slab interactions were compared. The efficient numerical modeling method was selected and then applied to the parametric study. The influence of the composite slab, the bottom flange bolts, the shear composite ratio and the web hole shape on the seismic performance of the bottom flange bolted composite beam connections were investigated. A hogging strength calculation method was then proposed based on numerical results.

Application of a ductile connection system to steel MRF strengthened with hinged walls

  • Zhi Zhang;Yulong Feng;Dichuan Zhang;Zuanfeng Pan
    • Steel and Composite Structures
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    • v.51 no.5
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    • pp.487-498
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    • 2024
  • Steel moment resisting frames (MRFs) typically have inter-story drift concentrations at lower stories during earthquakes as found from previous research. Hinged walls (HWs) can be used as structural strengthening components to force the MRFs deform uniformly along the building height. However, large moment demands are often observed on HWs and make the design of HWs non-economical. This paper proposes a method to reduce the moment demand on HWs using a ductile connection system between the MRFs and the HWs. The ductile connection system is designed with a yield strength and energy dissipation capacity, for the purpose of limiting the seismic forces transferred to the HWs and dissipating seismic energy. Nonlinear time history analyses were performed using 10 far-filed earthquakes at maximum considered earthquake level. The analysis results show that the proposed ductile connection system can reduce: (1) seismic moment demands in the HWs; (2) floor accelerations; (3) the connection force between HWs and MRFs.

Structural Performance of Stud Shear Connections using SHCC between Existing School Building Frame and Seismic Retrofitting Elements (기존 학교건물 골조와 내진보강요소 일체화를 위한 변형경화형 시멘트 복합체를 적용한 스터드 전단 접합부의 구조성능)

  • Kim, Sung-Ho;Yun, Hyun-Do
    • Journal of the Korean Institute of Educational Facilities
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    • v.20 no.4
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    • pp.35-43
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    • 2013
  • Some results of experimental investigation conducted to assess the effect of cement composite strength and ductility on the shear behavior and crack-damage mitigation of stud connections between existing reinforced concrete frame in school buildings and seismic strengthening elements from cyclically direct shear tests are described. The cement composite strengths include 50 for medium strength and 70 MPa for high strength. Two types of cement composites, strain-hardening cement composite (SHCC) and non-shrinkage mortar, are used for stud shear connection specimens. The special SHCCs are reinforced with hybrid 0.2% polyethylene (PE) and 1.3% polyvinyl alcohol (PVA) fibers at the volume fraction and exhibits tensile strain capacity ranging from 0.2 to 0.5%. Test result indicates that SHCC improves the seismic performance and crack-damage mitigation of stud shear connections compared with stud connections with non-shrinkage mortar. However, the performance enhancement in SHCC stud connections with transverse and longitudinal reinforcements is less notable for those without additional reinforcement.

Seismic Performance of HyFo Beam with High Depth-to-SRC Column Connections (춤이 큰 하이브리드 합성보와 SRC기둥 접합부의 내진성능에 관한 연구)

  • Kim, Sung Bae;Jeon, Yong Han;Cho, Seong Hyun;Choi, Young Han;Kim, Sang Seup
    • Journal of Korean Society of Steel Construction
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    • v.29 no.2
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    • pp.135-145
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    • 2017
  • This study is a secondary study that is a cyclic seismic test of High depth hybrid composite beam and column connection after the primary bending strength test of a high depth Hybrid composite beam. Total of 3 seismic test specimens were prepared to cyclic test. The bracket and beam web spliced by high strength bolt and the bracket and beam upper flange was spliced by welding. Test results showed that the seismic strength was higher than the plastic moment($M_p$) in the positive negative moment section, the requirement of composite intermediate moment frame wes satisfied. Therefore, the requirement of intermediate moment frame can be secured by applying the details of connection of this study results.

Dynamic Behavior of 2D 8-Story Unbraced Steel Frame with Partially Restrained Composite Connection (합성반강접 접합부를 갖는 2차원 8층 비가새 철골골조의 동적거동)

  • Kang, Suk Bong;Lee, Kyung Taek
    • Journal of Korean Society of Steel Construction
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    • v.19 no.5
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    • pp.503-513
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    • 2007
  • The seismic responses of a building are affected by the connection characteristics that have effects on structural stiffness. In this study, push-over analysis and time history analysis were performed to estimate structural behavior of 2D eight-story unbraced steel structures with partially restrained composite connections using a nonlinear dynamic analysis program. Nonlinear $M-{\theta}$characteristics of connection and material inelastic characteristics of composite beam and steel column were considered. The idealization of composite semi-rigid connection as fully rigid connection yielded an increase in initial stiffness and ultimate strength in the push-over analysis. In time history analysis, the stiffness and hysteretic behavior of connections have effects on base-shear force, maximum story-drift and maximum moment in beams and columns. For seismic waves with PGA of 0.4 g, the structure with the semi-rigid composite connections shows the maximum story-drift with less than the life safety criteria by FEMA 273 and no inelastic behavior of beam and column, whereas in the structure with rigid connections, beams and columns have experienced inelastic behaviors.

Cyclic testing of weak-axis steel moment connections

  • Lee, Kangmin;Li, Rui;Jung, Heetaek;Chen, Liuyi;Oh, Kyunghwan
    • Steel and Composite Structures
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    • v.15 no.5
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    • pp.507-518
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    • 2013
  • The seismic performance of six types of weak-axis steel moment connections was investigated through cyclic testing of six full-scale specimens. These weak-axis moment connections were the column-tree type, WUF-B type, FF-W type, WFP type, BFP-B type and DST type weak-axis connections. The testing results showed that each of these weak-axis connection types achieved excellent seismic performance, except the WFP and the WUF-B types. The WFP and WUF-B connections displayed poor seismic performance because a fracture appeared prematurely at the weld joint due to stress concentrations. The column-tree type connection showed the best seismic behavior such that the story drift ratio could reach 5%.