Cost Optimization of Steel Beam-to-Column Connections using AVOA

The joint-bolt-African Vulture optimization algorithm(AVOA)model is proposed for the design of building connections to improve the stability of steel beam-to-column connections.For this algorithm,the type of steel is first determined,and the number of bolts needed by the corresponding steel type is referenced in Eurocode 3.Then,the bearing capacity of the joint can be calculated.The joint-bolt-AVOA model is established by substituting the bolt number required by the steel into the algorithm to obtain the optimal bolt number required while ensuring joint stability.The results show that the number of bolts required by the joint-bolt-AVOA model based on the stability of steel is lower than that calculated by Eurocode 3.Therefore,AVOA can effectively optimize the number of bolts needed in building connections and save resources.

Experimental study on full-scale steel beam-to-column moment connections

Ten full-scale steel beam-to-column moment connections used in moment-resisting frames （MRFs） were tested to study the failure process, failure mode, strength and plastic rotation capacity. The specimens include one traditional welded flange-bolted web connection, one traditional fully welded connection, four beam flange strengthened connections, three beam flange weakened connections, and one through-diaphragm connection. The test results show that the connections with flange cover plates or with partly cut beam flanges satisfy the beam plastic rotation demand for ductile MRFs. From the measured stress profiles along the beam flange and beam web depth, the mechanics of brittle fracture at the end of the beam is discussed. Design recommendations for steel beam-to-column moment connections are proposed.

Strengthening Steel Joint of Architectural Structure under Loading Condition

Through the comparative analysis of steel plate reinforced, ceramics reinforced and non- reinforced joints under loading condition, the feasibility of strengthening steel joint of architectural structure was studied. By using element birth and death technology simulation of the finite element software ANSYS, it is found that when the reinforced structure is 10 mm in thickness and using steel structure to reinforce the concemed areas, the equivalent stress in concerned regionals reduces by 31.1% compared with that when the structure is not reinforced. When reinforced with ceramics, the equivalent stress in concerned regionals reduces by 24.1% compared with that reinforced with steels; when the reinforced structure is 20 mm in thickness using steels to reinforce the concerned area, the equivalent stress in concerned regionals reduces by 39.4% compared with that when the structure is not reinforced. When using ceramics to reinforce the concerned areas, the eauivalent stress only decreases by 3.7% compared with that reinforced with steels.

nvestigation of Structural Steel Webs for Punching Shear

Shear tab connections or simple connections are widely used in structural steel structures. There are several limit states associated with these connections such bolt shear, bolt bearing, block shear, shear yielding and shear rupture. A modified version of the shear tab has been developed during the last decade, which is extended shear tab connections. In developing design provisions for the extended shear tab connections, experimental work showed that there are additional limit states other than those mentioned above that limit the capacity of the extended shear connection. Extended shear tab connections could be used to frame beam-to-column or beam-to-girder. In the case where a beam is framed into girder, a new limit state develops in the web of the supporting girder. This limit state is punching shear of the supporting girder web which is due to a higher moment. The higher moment in extended shear tab connections is due to the larger moment arm （eccentricity） from the bolt line, the location of the shear force, to the support, which is in this case the girder＇s web. This study investigates the supporting girder web using experimental work, finite element analysis, and yield line theory. This paper shows the result of this investigation and proposes an evaluation of the web capacity equation which should be used when calculating the beam-to-girder connection capacity.

Seismic behavior and mechanism analysis of innovative precast shear wall involving vertical joints

To study the seismic performance and load-transferring mechanism of an innovative precast shear wall(IPSW) involving vertical joints, an experimental investigation and theoretical analysis were successively conducted on two test walls. The test results confirm the feasibility of the novel joints as well as the favorable seismic performance of the walls, even though certain optimization measures should be taken to improve the ductility. The load-transferring mechanism subsequently is theoretically investigated based on the experimental study. The theoretical results show the load-transferring route of the novel joints is concise and definite. During the elastic stage, the vertical shear stress in the connecting steel frame(CSF) distributes uniformly; and each high-strength bolt(HSB)primarily delivers vertical shear force. However, the stress in the CSF redistributes when the walls develop into the elastic-plastic stage. At the ultimate state, the vertical shear stress and horizontal normal stress in the CSF distribute linearly; and the HSBs at both ends of the CSF transfer the maximum shear forces.

Cyclic test and numerical study of seismic performance of precast segmental concrete double-columns

The comparative research on the seismic performance of grouted sleeve connected pier(GS)and prestressed precast segmental concrete pier(PC)is mostly carried out by numerical simulation.In this study,the GS pier and the PC pier of the new railway project from Hetian to Ruoqiang are taken into consideration.Two kinds of 1/5-scale assembled double-column specimens are made,and the quasi-static tests are carried out.The overall seismic performance of the two spliced piers is studied,and compared in terms of failure mechanism,bearing capacity,ductility,stiffness and energy dissipation capacity.The results show that the failure modes of both GS pier and PC pier are characterized by bending.However,the specific failure location and form are different.The GS pier presents a complete hysteretic curve,large equivalent stiffness and strong energy dissipation capacity.The hysteretic area of the PC pier is small.However,it has good self-reset ability and quasi-static residual displacement.Finite element models are set up using DispBeamColumn fiber elements and ZeroLength elements.The models that are calibrated with the test data can effectively simulate the damage development under monotonic loading.The load−displacement curves are in good agreement with the backbone curves of the test results.