In the Eccentric braced FRAMEs (EBFs), which one end of the link beam is connected to a column, the safety of the link-to-column connection is a requirement for the ductile and safe performance of the EBF. But among of the tests that have been implemented on this connection yet, because of the intensity of forces on vulnerable region of the link-to-column connection, the tested specimens were confronted with brittle and sudden failures. So it seems that the reduced beam section (RBS) can be a suitable solution for raising this problem, by concentrating flexural stresses at a location away from the connection, in flexural yielding link beams. Therefore in this paper, the possibility of keeping the plastic hinge away from the location of link-to-column connection, in the meanwhile achieving the required plastic rotation of link beam, by using the RBS connection, were investigated. This evaluation was done by using a finite element program ETABS and with nonlinear static analysis (pushover) for a DUAL system of special moment FRAME and special eccentric braced FRAME. According to the present work, the models with RBS by earlier developing the hinge at the RBS region, delay yielding occurrence of link at the column face. So the yielding does not occur at the column face, at least prior to achieving the moment at the location of RBS region to 1.1 times of its expected plastic moment capacity.

This paper is an investigation ofL-DUAL FRAMEs with respect to a function-valued inner product, the so calledL-bracket product on L2(G), where G is a locally compact abelian group with a uniform latticeL. We show that several well known theorems for DUAL FRAMEs and DUAL Riesz bases in a Hilbert space remain valid forL-DUAL FRAMEs and L-DUAL Riesz bases in L2(G).

Steel Plate Shear Wall (SPSW) is an emerging seismic load-resistant system that, compared to other systems, enjoys the advantages of stable ductile behavior, fewer detailing requirements, rapid constructability, and economy. American seismic provisions decree that a SPSW should be designed as a moment FRAME with a web infill plate. Specifically, in case of buildings taller than 160 ft, it decrees that a DUAL system must be used. This paper presents a method of Performance-Based Plastic Design (PBPD) to design steel moment FRAME-SPSW as a DUAL lateral load-resisting system. PBPD method uses pre-selected target drift and yield mechanism as its main criteria. For a specified hazard level, the design base shear is calculated based on energy work balance method, employing pre-selected target drift. Plastic design of DUAL FRAME system has been performed to meet the pre-selected yield mechanism. As presented in the paper, design procedure involves solving a system of five equations with five variables to determine the proportion of SPSW and moment FRAME shear, shear wall thickness, and beam/ column sections. It has been considered that a four-story structure is designed with the proposed method. Seismic performance of this DUAL FRAME system, designed with the proposed method, is evaluated by nonlinear static and dynamic analysis for both Design Basis Earthquake (DBE) and Maximum Credible Earthquake (MCE). Result analysis is in accord with the assumptions, satisfying all the performance objectives. PBPD is a direct design method in which no iteration is needed to achieve the performance objectives. Determining the proportion of SPSW and moment FRAME shear is an exclusive capability of this procedure.

This article presents an optimization problem for accomplishing seismic design of Reinforced Concrete (RC) DUAL systems and RC FRAMEs. The charged system search algorithm is chosen for the optimization. An efficient structural modeling is also presented for this purpose. Here, first databases are constructed according to ACI seismic design criteria for beams, columns and shear walls. Formulations for optimum seismic design of DUAL systems (shear wall-FRAME) are proposed. With some manipulations on these formulations, optimal seismic design of RC moment resisting FRAMEs is also performed. This procedure is together with ordinary design constraints and principal seismic design constraints. These constraints consist of beams, columns, shear wall design criteria, and some seismic design provisions. Cost of the structure is defined as the objective function.Based on the results of the design examples, the proposed methodology can be considered as a suitable practical approach for optimal seismic design of reinforced concrete moment resisting FRAMEs and DUAL structural systems consisting of structural wall.

In the present paper, the focus is on the evaluation of steel DUAL-system FRAME buildings using four main types of structural analysis (Linear Static, Linear Dynamic, Nonlinear Static and Nonlinear Dynamic Analyses) with regard to "Seismic Rehabilitation Code for Existing Buildings in Iran" (based on FEMA 273 and 356) where the first two authors of the article tend to follow the previous work (Section 2). The difference of the results taken from these four types of analyses and also seismic performance of the DUAL-system buildings will be studied in both linear and nonlinear treatments. Three 2D models which include 3 common DUAL-system buildings (5, 10 and 15-story) have been chosen and designed subjected to earthquake based on the Standard No. 2800 of Iran (3rd revision). Then, the 2D models have been analyzed and controlled according to "Seismic Rehabilitation Code for Existing Buildings". The selected rehabilitation goal for this research is Fair (Controlling Life Safety and Collapse Prevention in two hazard levels derived from PSHA analysis). Based on the research results, the main role of lateral load-bearing is on bracing members. The linear analysis of bracing members evaluation, has a low accuracy, in evaluation of columns the results derived from linear static analysis shows more accuracy than linear dynamic and nonlinear static analyses. Also, the accuracy of nonlinear static analysis decreases when the number of stories increases.