Seismic Behavior of Top-weld Bottom-bolt Joints between CFST Columns and H-beams

Abstract In recent decades, connections between concrete-filled steel tubular columns (CFST) and H-steel beams have been well designed and implemented. However, owing to poor construction quality, brittle failure often occurs at weld seams. In this study, an innovative joint was developed to connect CFST columns and H-steel beams using a top-weld bottom-bolt (TWBB) connection to minimize the effect of welding quality on the seismic resistance of joints. Six specimens were designed for cycle-reversed loading tests to discuss the seismic performance of this joint. Four configurations, including different connection methods, beam heights, column forms, and stiffener thicknesses, were considered in the test. The impacts of different configuration forms on the failure mode, strength, stiffness, ductility, and energy dissipation of the specimens were evaluated. The test results demonstrated that the columns with or without concrete had a significant effect on the deformation capacity. However, a smaller effect was observed on other indicators. The replacement of the through-diaphragm and an increase in the beam height adversely influenced the ductility of the joint. Moreover, changing the stiffener thickness and using a full-bolted connection affected the failure mode. The joint type analyzed in this study satisfies the strong column–weak beam design criterion and the related seismic provisions.

Download Full-text

Seismic Damage Investigation of Spatial Frames with Steel Beams Connected to L-Shaped Concrete-Filled Steel Tubular (CFST) Columns

Applied Sciences ◽

10.3390/app8101713 ◽

2018 ◽

Vol 8 (10) ◽

pp. 1713 ◽

Cited By ~ 11

Author(s):

Jicheng Zhang ◽

Yong Li ◽

Yu Zheng ◽

Zhijie Wang

Keyword(s):

Finite Element ◽

Frame Structures ◽

Steel Beams ◽

Element Analysis ◽

Testing Specimen ◽

Tubular Columns ◽

Finite Element Software ◽

Fea Model ◽

Composite Frames ◽

Cfst Columns

Currently, the frame structures with special-shaped concrete-filled steel tubular columns have been widely used in super high-rise buildings. Those structural members can be used to improve architectural space. To investigate the seismic behavior of spatial composite frames that were constructed by connecting steel beams to L-shaped concrete-filled steel tubular (CFST) columns, a finite element analysis (FEA) model using commercial finite element software ABAQUS was proposed to simulate the behavior of the composite spatial frames under a static axial load on columns and a fully-reversed lateral cyclic load applied to frames in this paper. Several nonlinear factors, including geometry and material properties, were taken into account in this FEA model. Four spatial specimens were designed, and the corresponding experiments were conducted to verify the proposed FEA model. Each testing specimen was two-story structure consisting of eight single span steel beams and four L-shaped CFST columns. The test results showed that the proposed FEA model in this paper could evaluate the behavior of the composite spatial frames accurately. Based on the results of the nonlinear analysis, the stress developing progress of columns is investigated. The load transferring mechanism and failure mechanism are also determined. The results are discussed and conclusions about the behavior of those spatial frame structures are presented.

Download Full-text

Static Behavior of a Modified Through-Core Connection between CFST Column and Composite Beam

Advances in Civil Engineering ◽

10.1155/2019/8314543 ◽

2019 ◽

Vol 2019 ◽

pp. 1-18

Author(s):

Qi-shi Zhou ◽

Hua-wei Fu ◽

Xu-hong Zhou ◽

Yu-jie Yu ◽

Qian-ren Wang

Keyword(s):

Load Transfer ◽

Steel Beams ◽

Load Bearing ◽

Rigid Connection ◽

Rc Slab ◽

Internal Forces ◽

Loading Tests ◽

Cfst Columns ◽

Concrete Filling ◽

Connection Design

Through-core connection has been proven to be an ideal solution to ensure a rigid connection between steel beams and CFST columns. However, the traditional through-core connection sometimes encounters concrete filling problems. A modified through-core connection design with details of reduced flange width was therefore proposed. Through-core reinforcements were added as supplements for tension load transfer. The monotonic loading tests and comprehensive FE simulations were performed to investigate the load bearing performance and working mechanism of this modified connection. The results indicated that the modified through-core connection presented plasticity hinge failure at the beam end and crack formulation and progradation at the RC slab. The reduced flange width reduced the strength of the connection, but the reduction extent was limited. Due to the through-core construction, the majority of internal forces at the beam were directly transferred into the column. The through-core reinforcement can effectively participate in load bearing after the connection yields. The flange width reduction extent and the length of the reduction region must be controlled to ensure sufficient connection strength. The number of shear studs and TC reinforcements can influence the load bearing ability, and design suggestions are provided for the modified through-core connection.

Download Full-text

Retrofitting of RCC Building for strong column weak Beam Design Criterion

International Journal of Innovative Technology and Exploring Engineering - Special Issue ◽

10.35940/ijitee.b6446.129219 ◽

2019 ◽

Vol 9 (2) ◽

pp. 470-474

Keyword(s):

Structural Damage ◽

Design Criterion ◽

Earthquake Resistance ◽

Seismic Load ◽

High Rise ◽

Weak Beam ◽

Beam Design ◽

Materials Used ◽

Earthquake Zone ◽

Seismic Forces

Reconstruction is a technical intervention in building structural systems that improves shock resistance by optimizing strength, ductility and seismic loading. The strength of a building results from the size of the structure, the material, the shape and the number of structural elements. The ductility of the building comes from good details, materials used, earthquake resistance, etc. The seismic load is generated by the seismic activity of the site, the quality of the building, the importance of the building, and the degree of earthquake resistance. In India, high rise structures are often built because of huge amount of cost and insufficiency of land. In order to take advantage of the largest land area, builders and architects usually propose high-rise building planning configurations. These buildings were built in earthquake-prone areas and may be get fail during the earthquake. Earthquakes occur naturally and can produce the forces which can cause damage in the structure. With proper design and structural component details, the building should be safe for life in order to have a malleable failure form. The knowledge of seismic forces is that the structure should be analyzed and designed to resist the seismic forces, with minimum damage and forces due to maximum consideration of the seismic forces, with some recognized structural damage but no collapse. This thesis involves Srinagar location survey which is in earthquake zone V. This exploration shows how easy an assignment for analysis that can be used to estimate the seismic resistance of existing or modified systems. The thesis analysis a detailed non-linear analysis of part of the structure for.

Download Full-text

Preliminary Research on Effective Length of Concrete Filled Steel Tubular Columns in Sway Frame

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.446-449.318 ◽

2012 ◽

Vol 446-449 ◽

pp. 318-321

Author(s):

Yan Li Shi ◽

Feng Wang ◽

Wen Da Wang

Keyword(s):

Steel Structure ◽

Current Approach ◽

Effective Length ◽

Steel Beams ◽

Engineering Practice ◽

Tubular Columns ◽

Composite Frames ◽

Composite Frame ◽

Cfst Columns ◽

Linear Buckling Analysis

The effective length of concrete filled steel tubular (CFST) frame columns is a key parameter to determine its ultimate strength for engineering design. There was no special design code, so engineers usually got the values according with specification for steel structure. This may cause error in some degree. Based on liner and non-linear buckling analysis respectively, the overall stability of a typical planar composite frame with CFST columns and steel beams was performed in this paper. By comparing the results of finite element method with current approach, some primary conclusions were given to refer for engineering practice on the composite frames.

Download Full-text

Realization of Strong Column-Weak Beam Failure Mode for Concrete-Filled Square Steel Tubular Frame Structure

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.446-449.424 ◽

2012 ◽

Vol 446-449 ◽

pp. 424-428 ◽

Cited By ~ 3

Author(s):

Jing Bo Liu ◽

Xue Li

Keyword(s):

Failure Mode ◽

Axial Compression ◽

Compression Ratio ◽

Frame Structure ◽

Frame Structures ◽

Strength Ratio ◽

Axial Compression Ratio ◽

Weak Beam ◽

Composite Frames ◽

Beam Design

Strong column-weak beam failure mode is considered to be a preferable mode for its large capability to absorb earthquake energy and prevent collapse. However, for composite frames composed of steel-concrete composite beams and concrete-filled steel tubular (CFST) columns, strong column-weak beam design methods are not given in Chinese codes. The column-to-beam strength ratio is one of the most important factors that influence the failure mode of frame structures. Moreover, large axial compression ratio of columns may cut down the actual bending capacity of columns, and thus has an adverse effect upon the realization of strong column-weak beam failure mode. In order to investigate the influence of column-to-beam strength ratio and axial compression ratio on the failure mode of concrete-filled square steel tubular frame structures, pushover analysis of a five-story three-bay composite frames with various column-to-beam strength ratios and axial compression ratios are carried out. Based on the analysis results, suggestions about the reasonable value of column-to-beam strength ratio with different axial compression ratios of columns are given to ensure the realization of strong column-weak beam failure mode for concrete-filled square steel tubular frame structures.

Download Full-text

Structural behavior of alternative low floor height system using structural "tee," half precast concrete, and horizontal stud

Canadian Journal of Civil Engineering ◽

10.1139/l04-095 ◽

2005 ◽

Vol 32 (2) ◽

pp. 329-338 ◽

Cited By ~ 11

Author(s):

Young K Ju ◽

Sang-Dae Kim

Keyword(s):

Composite Beam ◽

Precast Concrete ◽

Steel Structure ◽

Monotonic Loading ◽

Concrete Slabs ◽

Steel Beams ◽

Height System ◽

Loading Tests ◽

Beam Height ◽

Storey Building

Conventional composite construction consisting of steel beams and concrete slabs has been widely used throughout the world. When compared with a concrete flat-slab structure, however, the reduced beam height is a significant problem and is particularly important in a city where land prices are higher because a height reduction of 15 cm per storey can lead to a 750 cm reduction in the total height for a 50 storey building (equivalent to two storeys). In this paper a newly developed composite beam, the technical, economical, and convenient (TEC) beam, is proposed and experimentally investigated using a series of monotonic loading tests. The results show that the capacity of the proposed system is in agreement with design code predictions, and the system demonstrates a reliable composite behavior between steel beam and concrete slab.Key words: composite beam, steel structure, monotonic loading, flexural capacity.

Download Full-text

Review of Fire Performance Experiment of Concrete-Filled Steel Tubular Columns

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.638-640.1397 ◽

2014 ◽

Vol 638-640 ◽

pp. 1397-1401

Author(s):

Kai Xiang ◽

Guo Hui Wang ◽

Yan Chong Pan

Keyword(s):

Load Ratio ◽

Experimental Results ◽

Research Progress ◽

Future Research ◽

Fire Performance ◽

Cross Sectional ◽

Tubular Columns ◽

Cross Sectional Dimension ◽

Cfst Columns ◽

In Fire

This paper presents a review of research progress in fire performance of concrete-filled steel tubular (CFST) columns. Experimental results of CFST columns in fire are reviewed with influence parameters, such as heights, cross-sectional dimension, section types, concrete types, concrete strengths, load ratio, load eccentricity, fire exposed sides and so on. Some conclusions of CFST columns under fire conditions are summarized. Deficiencies in the fire performance experiments of CFST columns are identified, which provide the focus for future research in the field.

Download Full-text

Experimental Investigation of Stiffened Square CFST Columns under Axial Load

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.919-921.1794 ◽

2014 ◽

Vol 919-921 ◽

pp. 1794-1800

Author(s):

Xin Zhi Zheng ◽

Xin Hua Zheng

Keyword(s):

Experimental Investigation ◽

Bearing Capacity ◽

Cross Sections ◽

Axial Load ◽

Local Buckling ◽

Test Results ◽

Tubular Columns ◽

Economical Benefit ◽

Steel Consumption ◽

Cfst Columns

Abstract: 7 square steel tubular columns were tested to discuss the ultimate axial bearing capacity, ductility performance and the steel consumption under stiffened by steel belts and binding bars of different cross-sections. Test results indicate that only by increasing fewer amounts of steel usage, stiffened square CFST columns with binding bars can not only improve the overall effects of restraint and alleviate regional local buckling between the binding bars, but also improve the bearing capacity of concrete filled square steel tubular columns. The utility benefits and the economical benefit is considerable, deserving extensive use.

Download Full-text

A comparative study of beam design curves against lateral torsional buckling using AISC, EC and SP

Structural Mechanics of Engineering Constructions and Buildings ◽

10.22363/1815-5235-2019-15-1-25-32 ◽

2019 ◽

Vol 15 (1) ◽

pp. 25-32 ◽

Cited By ~ 2

Author(s):

Vera V Galishnikova ◽

Tesfaldet H Gebre

Keyword(s):

Steel Structures ◽

Reduction Factor ◽

Steel Beams ◽

Steel Beam ◽

Lateral Torsional Buckling ◽

Torsional Buckling ◽

Vertical Loading ◽

Beam Design ◽

Overall Stability

Introduction. Structural stability is an essential part of design process for steel structures and checking the overall stability is very important for the determination of the optimum steel beams section. Lateral torsional buckling (LTB) normally associated with beams subject to vertical loading, buckling out of the plane of the applied loads and it is a primary consideration in the design of steel structures, consequently it may reduce the load currying capacity. Methods. There are several national codes to verify the steel beam against LTB. All specifications have different approach for the treatment of LTB and this paper is concentrated on three different methods: America Institute of Steel Construction (AISC), Eurocode (EC) and Russian Code (SP). The attention is focused to the methods of developing LTB curves and their characteristics. Results. AISC specification identifies three regimes of buckling depending on the unbraced length of the member ( Lb ). However, EC and SP utilize a reduction factor (χ LT ) to treat lateral torsional buckling problem. In general, flexural capacities according to AISC are higher than those of EC and SP for non-compact sections.

Download Full-text