Pub Date : 2018-06-27DOI: 10.4995/ASCCS2018.2018.7085
A.N.T. Ihaddoudène, M. Saidani, J. Jaspart
Much work has been conducted in the past on the influence of the rigidity of structural joints on the behavior of steel frames. Buckling of a column is fundamental to the design of load bearing structures mainly when the analysis of such frames takes into account the effect of the connection flexibility. The present work deals with such an effect on the elastic buckling load of plane steel frames. The proposed model consists in the development of comprehensive approach taking into account, the effects of the joint rigidity, the elastic buckling load for both sway and non-sway frames. Only one element is required over the length of the element to model stability, which let to solve practical problem with little computational effort. Some practical formulas for determining critical load for plane steel frames are then presented. The elastic buckling load is found to be strongly affected by semi-rigid joints and reveals that the proposed model is computationally very efficient with the expressions presented being general.
{"title":"Influence of joint rigidity on the elastic buckling load of sway and non-sway steel frames","authors":"A.N.T. Ihaddoudène, M. Saidani, J. Jaspart","doi":"10.4995/ASCCS2018.2018.7085","DOIUrl":"https://doi.org/10.4995/ASCCS2018.2018.7085","url":null,"abstract":"Much work has been conducted in the past on the influence of the rigidity of structural joints on the behavior of steel frames. Buckling of a column is fundamental to the design of load bearing structures mainly when the analysis of such frames takes into account the effect of the connection flexibility. The present work deals with such an effect on the elastic buckling load of plane steel frames. The proposed model consists in the development of comprehensive approach taking into account, the effects of the joint rigidity, the elastic buckling load for both sway and non-sway frames. Only one element is required over the length of the element to model stability, which let to solve practical problem with little computational effort. Some practical formulas for determining critical load for plane steel frames are then presented. The elastic buckling load is found to be strongly affected by semi-rigid joints and reveals that the proposed model is computationally very efficient with the expressions presented being general.","PeriodicalId":320267,"journal":{"name":"Proceedings 12th international conference on Advances in Steel-Concrete Composite Structures - ASCCS 2018","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127873434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-27DOI: 10.4995/ASCCS2018.2018.7063
Mohammed A. Al-Shuwaili, A. Palmeri, Maria Teresa Lombardo
Push-out tests (POTs) have been widely exploited as an alternative to the more expensive full-scale bending tests to characterize the behaviour of shear connections in steel-concrete composite beams. In these tests, two concrete slabs are typically attached to a steel section with the connectors under investigation, which are then subjected to direct shear. The results allow quantifying the relationship between applied load and displacements at the steel-concrete interface. Since this relationship is highly influenced by the boundary conditions of POT samples, different experimental setups have been used, where the slabs are either restricted or free to slide horizontally, as researchers have tried to reduce any discrepancy between POT and full-scale composite beam testing. Based on a critical review of various POT configurations presented in the dedicated literature, this paper presents an efficient one-sided POT (OSPOT) method. While OSPOT and POT specimens are similar, in the proposed OPSPOT setup only one of the two slabs is directly loaded in each test, and the slab is free to move vertically. Thus, two results can be obtained from one specimen, i.e. one from each slab. A series of POTs and OSPOTs have been conducted to investigate the behaviour and the shear resistance of headed stud connectors through the two methods of testing. The results of this study than were compared with those of different POTs setups conducted by other researchers. The new OSPOT results show in general an excellent agreement with the analytical predictions offered by both British and European standards, as well as the estimated shear resistance proposed other researchers in the literature. These findings suggest that the proposed one-sided setup could be used as an efficient and economical option for conducting the POT, as it has the potential not only to double the number of results, but also to simplify the fabrication of the samples, which is important in any large experimental campaign, and to allow testing with limited capacity of the actuator.
{"title":"A novel one-sided push-out test for shear connectors in composite beams","authors":"Mohammed A. Al-Shuwaili, A. Palmeri, Maria Teresa Lombardo","doi":"10.4995/ASCCS2018.2018.7063","DOIUrl":"https://doi.org/10.4995/ASCCS2018.2018.7063","url":null,"abstract":"Push-out tests (POTs) have been widely exploited as an alternative to the more expensive full-scale bending tests to characterize the behaviour of shear connections in steel-concrete composite beams. In these tests, two concrete slabs are typically attached to a steel section with the connectors under investigation, which are then subjected to direct shear. The results allow quantifying the relationship between applied load and displacements at the steel-concrete interface. Since this relationship is highly influenced by the boundary conditions of POT samples, different experimental setups have been used, where the slabs are either restricted or free to slide horizontally, as researchers have tried to reduce any discrepancy between POT and full-scale composite beam testing. Based on a critical review of various POT configurations presented in the dedicated literature, this paper presents an efficient one-sided POT (OSPOT) method. While OSPOT and POT specimens are similar, in the proposed OPSPOT setup only one of the two slabs is directly loaded in each test, and the slab is free to move vertically. Thus, two results can be obtained from one specimen, i.e. one from each slab. A series of POTs and OSPOTs have been conducted to investigate the behaviour and the shear resistance of headed stud connectors through the two methods of testing. The results of this study than were compared with those of different POTs setups conducted by other researchers. The new OSPOT results show in general an excellent agreement with the analytical predictions offered by both British and European standards, as well as the estimated shear resistance proposed other researchers in the literature. These findings suggest that the proposed one-sided setup could be used as an efficient and economical option for conducting the POT, as it has the potential not only to double the number of results, but also to simplify the fabrication of the samples, which is important in any large experimental campaign, and to allow testing with limited capacity of the actuator. ","PeriodicalId":320267,"journal":{"name":"Proceedings 12th international conference on Advances in Steel-Concrete Composite Structures - ASCCS 2018","volume":"32 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113971038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-27DOI: 10.4995/ASCCS2018.2018.6925
I. Ahmed, K. Tsavdaridis, F. Neysari, J. Forth
This paper introduces a novel prefabricated and shallow steel-concrete composite flooring system which is consisted of two main structural components: two C-channel steel beams and a partially encased concrete floor. The concrete floor, which is in the form of T ribbed slab sections, was constructed using two types of concrete (reinforced normal concrete and reinforced lightweight aggregate concrete). The steel edge beams partially encase the floor slab and provide clear and straight finish edges. The floor slab spans to a maximum of 2.0m inclusive of the width of the steel edges with a finished depth of only 230mm. The unique features of the proposed system are reducing the weight and the number of erection lifts (during installation) by using lighter elements (lightweight concrete and shallow steel beams) while the wider possible units have been proposed to fit on transportation tracks; further reducing the extent of site works by pre-off site fabrication, examining the material cost against the fabrication and site erection costs. For the composite slab in bending, the longitudinal shear force is transferred by a unique shear mechanism which results from the special shear connectors. This paper includes the work of a total 2 full-scale push-out tests aimed at investigating the longitudinal shear behaviour of these novel flooring systems and the effects of additional shear connectors. An analytical work is also carried out to investigate the failure mechanism of the system.
{"title":"Push-Out Tests for a Novel Prefabricated Steel-Concrete Composite Shallow Flooring System","authors":"I. Ahmed, K. Tsavdaridis, F. Neysari, J. Forth","doi":"10.4995/ASCCS2018.2018.6925","DOIUrl":"https://doi.org/10.4995/ASCCS2018.2018.6925","url":null,"abstract":"This paper introduces a novel prefabricated and shallow steel-concrete composite flooring system which is consisted of two main structural components: two C-channel steel beams and a partially encased concrete floor. The concrete floor, which is in the form of T ribbed slab sections, was constructed using two types of concrete (reinforced normal concrete and reinforced lightweight aggregate concrete). The steel edge beams partially encase the floor slab and provide clear and straight finish edges. The floor slab spans to a maximum of 2.0m inclusive of the width of the steel edges with a finished depth of only 230mm. The unique features of the proposed system are reducing the weight and the number of erection lifts (during installation) by using lighter elements (lightweight concrete and shallow steel beams) while the wider possible units have been proposed to fit on transportation tracks; further reducing the extent of site works by pre-off site fabrication, examining the material cost against the fabrication and site erection costs. For the composite slab in bending, the longitudinal shear force is transferred by a unique shear mechanism which results from the special shear connectors. This paper includes the work of a total 2 full-scale push-out tests aimed at investigating the longitudinal shear behaviour of these novel flooring systems and the effects of additional shear connectors. An analytical work is also carried out to investigate the failure mechanism of the system.","PeriodicalId":320267,"journal":{"name":"Proceedings 12th international conference on Advances in Steel-Concrete Composite Structures - ASCCS 2018","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132290593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-27DOI: 10.4995/ASCCS2018.2018.6969
K. Cashell, R. Shamass
Stainless steel is increasingly popular in construction owing to its corrosion resistance, excellent mechanical and physical properties as well as its aesthetic appearance. The current paper is concerned with the use of stainless steel in steel-concrete composite beams, which is a new application. Current design codes for steel-concrete composite beams neglect strain hardening in the steel. Whilst this is a reasonable assumption for carbon steel, stainless steel is a very ductile material which offers significant levels of strain hardening prior to failure. Therefore, when current design provisions are applied to stainless steel composite beams, the strength predictions are generally inaccurate. The current study presents a simplified analytical solution that takes into consideration the strain hardening of stainless steel when bending moment capacity is calculated. A finite element model is developed and validated against a number of experimental results for composite beams. The validated numerical model is then used to investigate the accuracy of the proposed analytical solution. It is concluded that simplified analytical solution is reliable and provides a straightforward design tool for practicing engineers who wish to specify this novel construction form in appropriate applications.
{"title":"Bending Moment Capacity of Stainless Steel-Concrete Composite Beams","authors":"K. Cashell, R. Shamass","doi":"10.4995/ASCCS2018.2018.6969","DOIUrl":"https://doi.org/10.4995/ASCCS2018.2018.6969","url":null,"abstract":"Stainless steel is increasingly popular in construction owing to its corrosion resistance, excellent mechanical and physical properties as well as its aesthetic appearance. The current paper is concerned with the use of stainless steel in steel-concrete composite beams, which is a new application. Current design codes for steel-concrete composite beams neglect strain hardening in the steel. Whilst this is a reasonable assumption for carbon steel, stainless steel is a very ductile material which offers significant levels of strain hardening prior to failure. Therefore, when current design provisions are applied to stainless steel composite beams, the strength predictions are generally inaccurate. The current study presents a simplified analytical solution that takes into consideration the strain hardening of stainless steel when bending moment capacity is calculated. A finite element model is developed and validated against a number of experimental results for composite beams. The validated numerical model is then used to investigate the accuracy of the proposed analytical solution. It is concluded that simplified analytical solution is reliable and provides a straightforward design tool for practicing engineers who wish to specify this novel construction form in appropriate applications. ","PeriodicalId":320267,"journal":{"name":"Proceedings 12th international conference on Advances in Steel-Concrete Composite Structures - ASCCS 2018","volume":"14 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116811013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-27DOI: 10.4995/ASCCS2018.2018.7121
Qingjie Zhang, M. Schäfer
This paper compares the design of composite columns in steel and concrete based on EN1994-1-1 and Chinese JGJ138-2016. First, the application ranges of the codes are pointed out. Both codes contain the design of fully encased composite sections and concrete filled rectangular and circular tubes. However, there are different limitations on cross-section sizes, material strength classes, and others. JGJ138 has three separate chapters for the designs related to the three different types of columns. Eurocode 4 gives three different design methods: one general method based on nonlinear calculation, and two simplified methods based on European buckling curves or N-M iteration curves. For the materials, mechanical properties, such as design strength values, are compared based on the same material grade. For axial compression resistance and eccentrically compressive resistance, the two simplified methods from Eurocode 4 are compared with the design method according to JGJ138-2016 through theoretical and parameter studies. The influences of related parameters such as long-term effects, the buckling curves, and N-M iteration curves are also compared. For shear design, JGJ138-2016 considers mainly transverse shear resistances, while Eurocode 4 further considers shear connection and load introduction. The design transverse shear resistance is compared through theory.
{"title":"COMPARISON OF DESIGN FOR COMPOSITE COLUMNS IN STEEL AND CONCRETE ACCORDING TO EUROCODE 4 AND CHINESE DESIGN CODES","authors":"Qingjie Zhang, M. Schäfer","doi":"10.4995/ASCCS2018.2018.7121","DOIUrl":"https://doi.org/10.4995/ASCCS2018.2018.7121","url":null,"abstract":"This paper compares the design of composite columns in steel and concrete based on EN1994-1-1 and Chinese JGJ138-2016. First, the application ranges of the codes are pointed out. Both codes contain the design of fully encased composite sections and concrete filled rectangular and circular tubes. However, there are different limitations on cross-section sizes, material strength classes, and others. JGJ138 has three separate chapters for the designs related to the three different types of columns. Eurocode 4 gives three different design methods: one general method based on nonlinear calculation, and two simplified methods based on European buckling curves or N-M iteration curves. For the materials, mechanical properties, such as design strength values, are compared based on the same material grade. For axial compression resistance and eccentrically compressive resistance, the two simplified methods from Eurocode 4 are compared with the design method according to JGJ138-2016 through theoretical and parameter studies. The influences of related parameters such as long-term effects, the buckling curves, and N-M iteration curves are also compared. For shear design, JGJ138-2016 considers mainly transverse shear resistances, while Eurocode 4 further considers shear connection and load introduction. The design transverse shear resistance is compared through theory. ","PeriodicalId":320267,"journal":{"name":"Proceedings 12th international conference on Advances in Steel-Concrete Composite Structures - ASCCS 2018","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125627148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-27DOI: 10.4995/asccs2018.2018.7014
Clemence Lepourry, H. Somja, P. Keo, P. Heng, Franck Palas
In usual concrete buildings, medium to long span slabs can only be achieved by using prestressed beams. However, these elements are heavy, making their handling expensive; the cladding of these beams to vertical elements creates several difficulties, particularly in case of moment resisting frames; at last, their precamber implies a cautious management of the concreting and is a source of defects. Steel-concrete composite beams may offer an alternative, with similar performances. However they are not considered by concrete builders, because specific tools and skills are needed to erect them on site. Moreover usual composite members require a supplementary fire protection, which is costly and unsightly. This article presents an innovative steel-concrete moment resisting portal frame that overcomes these difficulties. It is based on composite tubular columns, and a composite beam made of a U-shaped steel profile used as permanent formwork to encase a concrete beam. This steel-concrete duality of beams allows an erection on site without any weld or bolt by a wise positioning of the construction joints. Moreover, as the resistance to fire is ensured by the concrete beam, the system does not require any additional fire protection. Finally, as only steel elements have to be handled on site, there is no need of heavy cranes. This system has been used to build a research center near Rennes, in France. As it is not covered in present norms, an experimental validation was required. After a detailed description of the structural system, the full-scale tests which have been performed are presented : - A series of asymmetrical push-out tests in order to determine the behaviour and resistance of shear connectors; - One 6-point bending test made to investigate the resistance of the USCHB under sagging bending moment; Two tests of the beam-column joint.
{"title":"An innovative concrete-steel structural system allowing for a fast and simple erection","authors":"Clemence Lepourry, H. Somja, P. Keo, P. Heng, Franck Palas","doi":"10.4995/asccs2018.2018.7014","DOIUrl":"https://doi.org/10.4995/asccs2018.2018.7014","url":null,"abstract":"In usual concrete buildings, medium to long span slabs can only be achieved by using prestressed beams. However, these elements are heavy, making their handling expensive; the cladding of these beams to vertical elements creates several difficulties, particularly in case of moment resisting frames; at last, their precamber implies a cautious management of the concreting and is a source of defects. Steel-concrete composite beams may offer an alternative, with similar performances. However they are not considered by concrete builders, because specific tools and skills are needed to erect them on site. Moreover usual composite members require a supplementary fire protection, which is costly and unsightly. This article presents an innovative steel-concrete moment resisting portal frame that overcomes these difficulties. It is based on composite tubular columns, and a composite beam made of a U-shaped steel profile used as permanent formwork to encase a concrete beam. This steel-concrete duality of beams allows an erection on site without any weld or bolt by a wise positioning of the construction joints. Moreover, as the resistance to fire is ensured by the concrete beam, the system does not require any additional fire protection. Finally, as only steel elements have to be handled on site, there is no need of heavy cranes. This system has been used to build a research center near Rennes, in France. As it is not covered in present norms, an experimental validation was required. After a detailed description of the structural system, the full-scale tests which have been performed are presented : - A series of asymmetrical push-out tests in order to determine the behaviour and resistance of shear connectors; - One 6-point bending test made to investigate the resistance of the USCHB under sagging bending moment; Two tests of the beam-column joint.","PeriodicalId":320267,"journal":{"name":"Proceedings 12th international conference on Advances in Steel-Concrete Composite Structures - ASCCS 2018","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126475405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-05DOI: 10.4995/ASCCS2018.2018.7287
Jiantao Wang, Qing Sun
Under violent earthquake motions, the severe damage in critical regions of structures could be ascribed to cumulative damage caused by cyclic loading. Using the high strength (HS) materials in concrete-filled steel tubular (CFST) columns is the effective way and popular tendency to promote the seismic behavior in anti-seismic design. In this paper, an experimental study on the hysteretic performance of high strength circular concrete-filled thin-walled steel tubular columns (HCFTST) columns was carried out. A total of six specimens were tested under constant axial compression combining cyclic lateral loading. The tested parameters were the different combinations of diameter-to-thickness (D/t) ratio, axial compression ratio (n) and concrete cylinder compressive strength (fc).The failure modes, load-displacement hysteretic curves, skeleton curves, dissipated energy and stiffness degradation were examined in detail. Through the experiment analysis result, it indicates that the ultimate limit state is reached as the severe local buckling and rupture of the steel tubes accompanying the core concrete crushing occur. Using high strength materials could have a larger elastic deformation capacity and the higher axial compression ratio within test scopes could motivate the potential of HS materials. In brief, the HCFTST columns with ultra-large D/t ratios under reasonable design could perform excellent hysteretic performance, which can be applied in earthquake-prone regions widely.
{"title":"Hysteretic performance research on high strength circular concrete-filled thin-walled steel tubular columns","authors":"Jiantao Wang, Qing Sun","doi":"10.4995/ASCCS2018.2018.7287","DOIUrl":"https://doi.org/10.4995/ASCCS2018.2018.7287","url":null,"abstract":"Under violent earthquake motions, the severe damage in critical regions of structures could be ascribed to cumulative damage caused by cyclic loading. Using the high strength (HS) materials in concrete-filled steel tubular (CFST) columns is the effective way and popular tendency to promote the seismic behavior in anti-seismic design. In this paper, an experimental study on the hysteretic performance of high strength circular concrete-filled thin-walled steel tubular columns (HCFTST) columns was carried out. A total of six specimens were tested under constant axial compression combining cyclic lateral loading. The tested parameters were the different combinations of diameter-to-thickness (D/t) ratio, axial compression ratio (n) and concrete cylinder compressive strength (fc).The failure modes, load-displacement hysteretic curves, skeleton curves, dissipated energy and stiffness degradation were examined in detail. Through the experiment analysis result, it indicates that the ultimate limit state is reached as the severe local buckling and rupture of the steel tubes accompanying the core concrete crushing occur. Using high strength materials could have a larger elastic deformation capacity and the higher axial compression ratio within test scopes could motivate the potential of HS materials. In brief, the HCFTST columns with ultra-large D/t ratios under reasonable design could perform excellent hysteretic performance, which can be applied in earthquake-prone regions widely.","PeriodicalId":320267,"journal":{"name":"Proceedings 12th international conference on Advances in Steel-Concrete Composite Structures - ASCCS 2018","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115171329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-05DOI: 10.4995/ASCCS2018.2018.7138
Dan Gan, Tao Zhang, Xu-hong Zhou, Ziqiang He
Concrete-filled steel tubes have been widely used all over the world due to their superior structural behaviour. To promote the use of ecofriendly materials and to reduce the use of concrete, this paper presents an innovative type of composite column, which can be referred as bamboo-concrete filled steel tubes. In this kind of column, concrete filled in the space between the external steel tube and the inner raw moso bamboo. Bamboo-concrete filled steel tubes inherit the merits of concrete-filled steel tubes such as high load-bearing capacity and ductility performance. Besides, global buckling behaviour of a bamboo column due to its relatively large slenderness can be significantly improved, and the bamboo column with nodes could provide confinement to the infilled concrete. This paper investigated the composite effect of bamboo-concrete filled steel tubular stub columns subjected to axial compression. In addition, concrete-filled double-skin steel tubular stub columns and hollow concrete-filled steel tubular stub columns were also tested for comparison. The main experimental parameter considered was the diameter-to-thickness ratio (D/t) of steel tube. Test results indicated that the composite columns with moso bamboo pipe as inner core elements showed better ductility than the hollow concrete-filled steel tubular stub columns. The bearing capacity and ductility visibly increased with decreasing of the D/t ratio.
{"title":"Experimental investigation on the bamboo-concrete filled circular steel tubular stub columns","authors":"Dan Gan, Tao Zhang, Xu-hong Zhou, Ziqiang He","doi":"10.4995/ASCCS2018.2018.7138","DOIUrl":"https://doi.org/10.4995/ASCCS2018.2018.7138","url":null,"abstract":"Concrete-filled steel tubes have been widely used all over the world due to their superior structural behaviour. To promote the use of ecofriendly materials and to reduce the use of concrete, this paper presents an innovative type of composite column, which can be referred as bamboo-concrete filled steel tubes. In this kind of column, concrete filled in the space between the external steel tube and the inner raw moso bamboo. Bamboo-concrete filled steel tubes inherit the merits of concrete-filled steel tubes such as high load-bearing capacity and ductility performance. Besides, global buckling behaviour of a bamboo column due to its relatively large slenderness can be significantly improved, and the bamboo column with nodes could provide confinement to the infilled concrete. This paper investigated the composite effect of bamboo-concrete filled steel tubular stub columns subjected to axial compression. In addition, concrete-filled double-skin steel tubular stub columns and hollow concrete-filled steel tubular stub columns were also tested for comparison. The main experimental parameter considered was the diameter-to-thickness ratio (D/t) of steel tube. Test results indicated that the composite columns with moso bamboo pipe as inner core elements showed better ductility than the hollow concrete-filled steel tubular stub columns. The bearing capacity and ductility visibly increased with decreasing of the D/t ratio.","PeriodicalId":320267,"journal":{"name":"Proceedings 12th international conference on Advances in Steel-Concrete Composite Structures - ASCCS 2018","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116970333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-05DOI: 10.4995/ASCCS2018.2018.7122
Liangjie Qi, Jonathan L. Paquette, M. Eatherton, R. Leon, T. Bogdan, N. Popa, E. Nunez
Recently completed experimental steel beam-column connection tests on the largest specimens of reduced-beam section specimens ever tested have shown that such connections can meet current seismic design qualification protocols, allowing to further extend the current AISC Seismic Provisions and the AISC Provisions for Prequalified Connections for Special and Intermediate Steel Moment Frames. However, the results indicate that geometrical and material effects need to be carefully considered when designing welded connections between very heavy shapes. Understanding of this behavior will ease the use of heavier structural shapes in seismic active areas of the United States, extending the use of heavy steel sections beyond their current use in ultra-tall buildings. To better interpret the experimental test results, extensive detailed finite element analyses are being conducted on the entire series of tests, which comprised four specimens with beams of four very different sizes. The analyses intend to clarify what scale effects, at both the material and geometric level, influence the performance of these connections. The emphasis is on modeling of the connection to understand the balance in deformation between the column panel zones and the reduced beam section, the stress concentrations near the welds, the effects of initial imperfections and residual stresses and the validity of several damage accumulation models. The models developed so far for all four specimens have been able to accurately reproduce the overall load-deformation and moment-rotation time histories.
{"title":"Analysis of Fracture Behavior of Large Steel Beam-Column Connections","authors":"Liangjie Qi, Jonathan L. Paquette, M. Eatherton, R. Leon, T. Bogdan, N. Popa, E. Nunez","doi":"10.4995/ASCCS2018.2018.7122","DOIUrl":"https://doi.org/10.4995/ASCCS2018.2018.7122","url":null,"abstract":"Recently completed experimental steel beam-column connection tests on the largest specimens of reduced-beam section specimens ever tested have shown that such connections can meet current seismic design qualification protocols, allowing to further extend the current AISC Seismic Provisions and the AISC Provisions for Prequalified Connections for Special and Intermediate Steel Moment Frames. However, the results indicate that geometrical and material effects need to be carefully considered when designing welded connections between very heavy shapes. Understanding of this behavior will ease the use of heavier structural shapes in seismic active areas of the United States, extending the use of heavy steel sections beyond their current use in ultra-tall buildings. To better interpret the experimental test results, extensive detailed finite element analyses are being conducted on the entire series of tests, which comprised four specimens with beams of four very different sizes. The analyses intend to clarify what scale effects, at both the material and geometric level, influence the performance of these connections. The emphasis is on modeling of the connection to understand the balance in deformation between the column panel zones and the reduced beam section, the stress concentrations near the welds, the effects of initial imperfections and residual stresses and the validity of several damage accumulation models. The models developed so far for all four specimens have been able to accurately reproduce the overall load-deformation and moment-rotation time histories. ","PeriodicalId":320267,"journal":{"name":"Proceedings 12th international conference on Advances in Steel-Concrete Composite Structures - ASCCS 2018","volume":"2013 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127348936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-05DOI: 10.4995/asccs2018.2018.7007
Mikihito Yoshida, Y. Nishimura
For the joints composed of steel beams and reinforced concrete columns, shear failure and bearing failure are the key failure modes. The shear failure indicates stable hysteresis loop without the strength degradation. On the other hand, the bearing failure mode indicates large pinching and strength degration after the attainment of the maximum load.Accordingly, bearing failure in the joints should not be caused in RCS system.To improve the bearing failure behavior of S beam - RC column joint, joint details using perfobond plate connectors were proposed. Perfobond plate connectors were attached on the upper and bottom flanges at right angles to the steel flange. The objective of this study is to clarify the effectiveness of proposed joints details experimentally and theoretically.Six specimens were tested. All specimens were T-shaped planar beam - column joints with 350mm square RC column and S beams with the width of 125mm and the depth of 300mm. The beams were all continuous through the column.Perfobond plate connectors were attached on the bottom flanges at right angles to the steel flange.Three holes were set up in the perfobond plate connectors. The experimental variable was the transverse reinforcement ratio of the joints. The transverse reinforcement ratio of the joints was 0.181% and 0.815%. For each transverse reinforcement ratio of the joints, specimen without the perfobond plate connectors, specimen with the perfobond plate connectors and specimen with the reinforcing bar inserted the hole of perfobond plate connectors were planned.For all specimens, the hysteresis loop showed the reversed S-shape. However, energy dissipation for specimens for specimens with perfobond plate connectors was larger than of specimen without perfobond plate connectors. Bearing strength of specimens with perfobond plate connectors was larger than that of specimen without perfobond plate connectors. From the test results, shear strength of concrete connector a hole was 0.7 times compression strength of concrete.On the other hand, shear strength of inserted reinforcing bar was 1.25 times shear strength of reinforcing bar.Based on the stress transferring mechanism and resistance mechanism of joints proposed by authors, the design formulae of joints with perfobond plate connectors were proposed.The predictions were shown to be in good agreement with the test results.
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