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IntroductionSeismic provisions in current building codes and standards include rules for design of structures using nonlinear response history analysis in some conditions. Due to the lack of recorded data for the design level earthquakes (which are usually rare events), it is critical to develop systematic methods and useful tools to select and modify from current ground motion databases to provide a group of earthquake motions that can realistically represent important aspects of the design motion controlling the nonlinear response of civil engineering facilities [1]. The best method for selecting and scaling ground motions will depend on the type of assessment being performed. ATC-58-1 identifies three types of performance assessment: intensity, scenario, and time-based. Intensity-based assessments are the most common of the three types and compute the response of a building and its components for a specified intensity of ground shaking (this approach is the focus of this paper). A scenario-based assessment computes the response of a building to a user specified earthquake event, which is typically defined by earthquake magnitude and the distance between the earthquake source and the building site. A risk-based (referred to as time-based assessment in ATC-58-1) assessment provides information on response over a period of time (e.g., annual rates). This is the most comprehensive type of assessment and involves a number of intensity-based assessments over the range of ground motion levels of interest [2]. Despite the scenario-based assessment which computes the response of a building based on a specific earthquake event, intensity and time-based assessments have been conducted subjecting to a group of records. Time-based assessment acquires information of all occurred earthquakes which have been utilized to adjust hazard curve of the assessed region; so, as much as records could be provided, the confidence level will promote, so many researchers attempts to enlarge records category to reduce record-by-record variations incorporated in this type of assessment. However, intensity-based assessment deal with number of records represented by intensity measures (IM), like peak ground acceleration, spectral acceleration on fundamental period of the model or etc., which are scaled associated to the intensity assumed target spectrum. Therefore, although enlarge-

In recent decades, different macro-models have been proposed for simulating the behaviour of concrete shear walls because of their significant role in the seismic performance of urban buildings. The ability of Timoshenko's beam theory to evaluate the behaviour of slender and moderate-aspect-ratio concrete shear walls was evaluated in this work. For this purpose, a non-linear displacement-based Timoshenko fibre element was first added to OpenSees software. A new constitutive model based on modified compression field theory was used for the stress–strain relationship of the materials. To validate the element and the materials used, the results of the numerical model were compared with a set of laboratory tests of concrete shear walls subjected to cyclic and seismic loads (shaking table tests). Evaluation of the numerical model and the experimental results revealed that the analysis procedure used to model the reinforced concrete walls predicted their overall and local responses with acceptable accuracy. It can thus be used as a reliable tool for the analysis of slender and moderate-aspect-ratio concrete shear walls.

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This study elucidates the behavior of flange plate connection between a steel beam and a welded box column. Four finite element models simulating an exterior connection were prepared and analyzed. On the basis of finite element results, two flange plate connection details which are the reinforcing plate length and plate-to-flange fillet weld geometry were improved. Then, two full-scale specimens with flange plate connections were tested using a standard connection requalification test protocol. The flange plate connections of test specimens achieved the AISC seismic provision requirements for special moment frames. Kim et al. [9,10] tested two full-scale moment connections to US box columns fabricated using pre-Northridge connection details. Test results revealed that both specimens failed by brittle fracture of complete joint penetration (CJP) welds between the beam flange and the column during a story drift angle of less than 1% rad, which resulted in no plastic rotation in the connections. KeywordsChen et al. [8] tested six large scale specimens of steel beam-to-box column connections. One of the test specimens was the unreinforced connection using pre-Northridge details, and other test specimens were the reinforced connections using rib plates or wing plates. The unreinforced connection was failed by fracture in the heat affected zone (HAZ) of the beam bottom flange during 2.3% story drift angel cycle.In the present study the behavior of a moment resisting connection, shown in Figure 1, has been investigated. This type of connection is mainly fabricated on site similar to a welded flange plate (WFP), which is considered as a prequalified connection in accordance with FEMA [11].The shapes of the top and bottom flange plates are different due to the field construction of the connection at the site. The geometry of these plates is considered in a manner that site welding in a horizontal position is possible for connecting flange plates to beam and column. The WFP connections using rectangular and trapezoidal shapes of flange plates connecting to the H shape columns have already been tested [12,13]. Evaluation of Welded Flange Plate Connections between Steel Beams and Box ColumnsA special welding sequence should be followed to join the continuity plates to the box column plate. As shown in Figure 2, after groove welds are performed to join the continuity plates to three plates of box column, the fourth plate should cuts into three segments. As shown in Figure 2, first, middle segment put into the place and CJP groove welds of continuity plates to this segment will be done. Finally, three segments will weld to each other.This study analytically and experimentally investigates the behavior of the WFP connections. On the base of finite element results, an improved WFP connection was proposed. Then, two full-scale specimens with flange plate connections were tested using a standard connection prequalification test protocol. The results of the specimen's hysteretic behavior were obtained and compared to the...

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