The shear stud arrangements on the steel plates are depicted in Figure 2. The nominal stud diameter and length were 25mm and 100mm, respectively. The characteristic never shear strength Qk of the shear studs, which depends on the concrete strength, was obtained from BS5950 [13]. In order to minimize the required anchorage length, the bearing strengths provided by the shear studs in both vertical and horizontal directions were considered and a maximum number of shear studs was provided in the plate anchors in accordance with the minimum allowable shear stud spacing [13], as shown in Figure 2.2.2. A Brief Introduction to the Finite Element ModelThree- and four-node SBETA elements [8] were used to simulate the concrete in the analysis.

The following factors were considered in the nonlinear concrete material model used in the analyses: (1) nonlinear behavior in compression including hardening and softening, (2) fracture of concrete in tension based on nonlinear fracture mechanics, (3) biaxial strength failure criterion, (4) reduction of compression strength after cracking, and (5) reduction of the shear stiffness after cracking (variable shear retention). In order to represent the unique properties of concrete produced in Hong Kong, the initial elastic modulus E0 and the peak strains ��c of the local concrete were estimated by the following equations [14], where fcu is the cube compressive strength of concrete:E0=6500|fcu|1/3[MNm2],��c=3.46|fcu|3/4Ec.(2)The tensile strength ft�� [15] and fracture energy Gf [16] were defined asft��=0.198fcu2/3[MNm2],Gf=0.000012fcu0.557[MNm].

(3)Poisson’s ratio and compression softening deformation of the concrete were taken as 0.2 and ?0.006m, respectively.Experimental results obtained by Lam et al. [3] have shown that bond slipping is quite significant for RC coupling beams. The main longitudinal reinforcement of the coupling beams was therefore modeled by the discrete reinforcement model which was able to consider the bond slip effects. The bond-slip relationship of the CEB-FIB model code 90 [17] was used in this analysis.Each steel plate was modeled using the bilinear steel von Mises model provided in ATENA, where the biaxial failure law was considered in conjunction with the bilinear stress-strain law that took into account both the elastic state and the hardening of steel. A Poisson’s ratio of 0.

3 was used in Drug_discovery considering the biaxial responses of steel plates.Rectangular shear stud elements with a combination of 4-node quadrilateral and 3-node triangular finite elements (as illustrated in Figure 3) were used to model the shear stud action. The flexible elements with material 2 were introduced as the media for the plate/RC load transfers that allowed for plate/RC interface slips. The elements with material 1 are much stiffer than material 2 and would undergo predominantly rigid body movement only.