## 3 Experimental Program  
### Design Procedure  
In the design of the speedBridge, a capacity design concept was adopted, such that the connection parts were designed to exhibit strength and stiffness comparable to or exceeding those of a beam without a hinge connection. Therefore, the moment resistance at the section where the pin exists needs to exceed the design plastic moment of the beam such that (see Figure 2)  
\[M_{c}\geq\alpha M_{pe}=\alpha ZF_{ye}=\alpha ZR_{y}F_{y} \tag{1}\]  
where \(M_{c}\) is the required moment resistance at the center of the connector, \(M_{pe}\) is the expected plastic moment, \(Z\) is the plastic section modulus of the beam, \(F_{ye}\) is the expected yield stress of beam flange, \(R_{y}\) is the ratio of the expected yield stress to the specified minimum yield stress, \(F_{y}\) is the specified minimum yield stress, and \(\alpha\) is a number greater than 1.0 to account for the possible reserve strength of the steel beam beyond its nominal yield strength. In this study, \(\alpha\) is taken as 1.1 to consider the hardening effect of the material. The factor \(R_{y}\) is taken as 1.2, which is specified in the Korean Design Code for Seismic Design of Steel Structures [21].  
The pin pulls the pin plates owing to the tension induced by the moment, and the tensile force is calculated according to the probable moment at the center of the connector, \(M_{c}\), and arm length, \(d_{c}\), as follows (see Figure 3):  
\[T=\frac{M_{c}}{d_{c}} \tag{2}\]  
The details of the connectors were designed based on American Institute of Steel Construction (AINC) specifications [22]. In this design of pin plates, the AINC specification for pin-connected members was applied. The design strength of the connectors is determined by the tensile strength, \(\phi P_{n}\), of the pin-connected members, and shall be the lower value determined according to the limit states of tensile rupture, shear rupture, bearing, and yielding (see Figure 3 for the fracture of pin plates). Moreover, in the design of the pin, the shear fracture and bearing of the pin were considered failure conditions.  
Figure 2: Capacity design of the speedBridge.  
The design considerations are summarized as follows:  
1. Pin plates (a) Fracture of net section (AASC Specification Section D5) \[P_{n}=F_{u}(2 tb_{e}),\ \phi=0.75\] (3) where \(b_{e}=2t+16\ \mathrm{mm}\ \leq b\), with \(b\) being the actual distance from the edge of the hole to the edge of the part measured in the direction normal to the applied force, and \(F_{u}\) is the specified minimum tensile stress of the pin plate. (b) Longitudinal shear rupture (AISC Specification Section D5) \[P_{n}=0.6F_{u}A_{sf},\ \phi=0.75\] (4) where \(A_{sf}=2t(a+d/2)\) is the area of the shear failure, with \(a\) being the shortest distance from the edge of the pinhole to the edge of the member measured parallel to the direction of the force. (c) Bearing of pin plates (AISC Specification Section J7) \[P_{n}=1.8F_{y}A_{pb},\ \phi=0.75\] (5) where \(A_{pb}=dt\) is the projected bearing area. (d) Yield of the gross section (AISC Specification D2) \[P_{n}=F_{y}A_{g},\ \phi=0.90\] (6) where \(A_{g}\) is the gross area. 2. Pin (a) Shear failure (AISC Specification Section J3.6) \[P_{n}=0.6F_{u,p}A_{pin},\ \phi=0.75\] (7) (b) Bearing of the pin \[P_{n}=1.8F_{y,p}A_{pb},\ \phi=0.75\] (8) where \(F_{y,p}\) is the specified minimum yield stress of the pin, \(F_{u,p}\) is the specified minimum tensile stress of the pin, \(A_{pin}\) is the area of the pin, and \(A_{pb}\) is the projected bearing area of the pin.  
Figure 3: Failure modes for pin plates. (**a**) Fracture of net section; (**b**) Longitudinal shear; (**c**) Bearing.