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The coupled steel plate shear wall (C-SPSW) configuration consisting of two SPSWs linked by coupling beams at the floor levels, in addition to providing architectural flexibility, has been shown to exhibit superior seismic performance. While the shear strength of the infill panels due to tension field action is the primary source of lateral load resistance in a C-SPSW, the moment resisting actions of the boundary frames and the coupling beams connections provide substantial strength for the system. As such, in order to achieve material-efficient designs, rational procedures are needed to explicitly account for this strength, while maintaining the desirable performance for various hazard levels. Similar to planar SPSWs, the C-SPSW systems have been designed using the conventional force-based design approach, which typically requires several iterations to optimize the design for performance and efficiency. This research employs the principles of plastic analysis to quantify the contribution of the frame action to the overall strength of C-SPSWs and adopts the philosophy of the performance-based plastic design (PBPD) methodology to develop procedures for the efficient seismic design of such systems. To investigate the effectiveness of the proposed design procedure, 8- and 12-story case study C-SPSWs were designed, and their numerical models were analyzed using pushover and response history analyses. The seismic performance of the prototypes were evaluated using two suits of ground motions representing 10/50 and 2/50 hazard levels. The analysis results indicated that the C-SPSWs designed using the proposed approach successfully met the desired performance objectives for both seismic hazard levels considered. [ABSTRACT FROM AUTHOR]

Having investigated the plastic behavior and mechanisms of steel plate shear walls with outriggers (SPSW-O) introduced in Part I, it was shown that such systems are considerably effective in improving the flexural stiffness of conventional SPSWs. This paper describes procedures for the efficient design of SPSW-Os employing the principles of plastic analysis and capacity design. While the primary motivation behind the use of SPSW-O configuration is to enhance the overturning stiffness of SPSWs and provide architectural flexibility, the rigidly connected outrigger beams introduce additional lateral force resistance to the system due to the frame action, which must be taken into account for an efficient design. As such, this part of the analytical investigation focuses on quantifying the contributions of the tension field action of the infill panels and moment-resisting action of the SPSW boundary frame and/or outrigger frames to the global strength of the four SPSW-O options discussed in part I. The proposed approach together with the knowledge generated in part I are utilized in developing efficient design procedures for the SPSW-O systems. Then, the proposed procedures are used to design 12- and 20-story case study buildings having four different SPSW-O options as their seismic force resisting systems. Additionally, two SPSWs without outriggers, herein referred to as free-standing SPSWs, are also designed for comparison purposes. The seismic performances of the prototype SPSW-Os are evaluated using nonlinear static and response history analyses, and are compared with those of the free-standing SPSWs. [ABSTRACT FROM AUTHOR]

Steel plate shear walls (SPSWs) are ductile and economical energy dissipating systems for buildings located in regions of high seismic risk. In spite of many advantages of SPSWs; however, their overturning stiffness is relatively low, especially when their width is narrow compared to the building height. Therefore, additional flexural stiffness must be provided to the system when designing narrow SPSWs. A logical solution that can be effectively used in SPSW systems is to rigidly connect the beams of adjacent bays to the columns of SPSWs (on both sides) forming an interacting system of SPSW and moment frame in which the adjacent beams act as outriggers resulting in an overall reduction of overturning in the SPSW. However, insufficient information exists on the behavior and efficiency of such structural systems, herein referred to as SPSW with outriggers (SPSW-O). This paper discusses four different potential SPSW-O options that can be used in mid- to high-rise buildings to enhance the flexural stiffness of the system. Plastic mechanisms, ultimate lateral load resistance and overturning stiffness of such systems are investigated, and key design parameters are identified through a combined analytical and numerical investigation. A parameter called the outrigger efficiency factor (OEF) is defined to quantify the contribution of the outrigger system to the overall overturning stiffness of a SPSW-O. Analytical expressions are derived for the lateral load resistance and OEF of the four SPSW-O options, and are then compared with numerical analysis results with reasonable agreement. Furthermore, parametric studies are performed to investigate the influence of a number of parameters on the overall behavior and characteristics of the SPSW-O systems. Parameters subject to investigation include height of the wall, outrigger beam and connection properties. [ABSTRACT FROM AUTHOR]

A large number of precast prestressed concrete multi-girder bridges were constructed in Alberta in the early 1960s. Major benefits of this type of construction included the elimination of the cast in place concrete bridge deck and the accelerated pace of construction in erecting the bridge. However, after providing 10 to 20 years of service, some of these bridges started to form longitudinal cracks in the deck directly over the girder joining shear key locations. Once a crack was formed in the shear keys, salt and water would penetrate the wearing surface and weaken the shear key grout. This brought about concerns regarding adequate load sharing among the girders and corrosion of the prestressing tendons within the girders. An extensive survey was undertaken to observe the longitudinal cracking on these bridge decks. The objectives of the field survey were to look for possible trends or relationships between various influencing parameters and the performance of these bridges. Field data were obtained from a visually selected sample survey and a comprehensive bridge record survey based on Alberta Transportation (Government of Alberta) bridge files. The parameters investigated for influence on bridge performance were span length, span width, bridge skew, service age, and traffic volume. Finally, the rehabilitation schemes used on these bridges in the past are described, and the strengths and weaknesses of each rehabilitation strategy are discussed. [ABSTRACT FROM AUTHOR]

Due to the ease of fabrication and construction, gusset plate connections with single-sided splice members are a popular connection type in building frames and light structures. However, this detail produces local out-of-plane eccentricity, which can be detrimental to the ultimate strength of the connections. This paper presents experimental, numerical, and analytical investigations of the compressive behaviour of eccentrically loaded gusset plate connections. Three full-scale tests were conducted, including two specimens with unstiffened splice members and the remaining one with stiffened splice members. The ultimate loads of the three specimens were found to be evidently less than the concentrically loaded specimen which has been earlier reported. Finite element (FE) models were then established, which were validated through comparisons against the test results. The sensitivity of the FE models to the initial imperfections was also studied. An extensive parametric study was subsequently performed, and the influences of varying gusset plate and splice member geometric configurations were discussed in detail. Three key failure modes were identified for the eccentrically loaded gusset plate connections, namely, Gusset–Splice Interactive Plastic Failure (G–SIPF), Splice Plastic Failure (SPF), and Gusset Plate Buckling (GPB). A set of design rules based on the nature of each failure mode was proposed accordingly, where good agreements were observed between the FE and the design results in terms of both the ultimate load and the governing failure mode. Worked examples were finally provided to clearly illustrate the proposed design procedure. [ABSTRACT FROM AUTHOR]

Abstract: A new approach is developed to implement the cohesive zone concept for the simulation of delamination in fibre composites or crack growth in adhesive joints in tension or shear mode of fracture. The model adopts a bilinear damage evolution law, and uses critical energy release rate as the energy required for generating fully damaged unit area. Multi-axial-stress criterion is used to govern the damage initiation so that the model is able to show the hydrostatic stress effect on the damage development. The damage material model is implemented in a finite element model consisting of continuum solid elements to mimic the damage development. The validity of the model was firstly examined by simulating delamination growth in pre-cracked coupon specimens of fibre composites: the double-cantilever beam test, the end-notched flexure test and the end-loaded split test, with either stable or unstable crack growth. The model was then used to simulate damage initiation in a composite specimen for delamination without a starting defect (or a pre-crack). The results were compared with those from the same finite element model (FEM) but based on a traditional damage initiation criterion and those from the experimental studies, for the physical locations of the delamination initiation and the final crack size developed. The paper also presents a parametric study that investigates the influence of material strength on the damage initiation for delamination. [Copyright &y& Elsevier]

Adoption of cylindrical shell structures for various load-resistance applications has enjoyed wide-spread acceptance in the field of civil, mechanical and aerospace engineering, mainly due to the exceptional structural efficiency of cylindrical shells to withstand significant longitudinal and circumferential in-plane loading without bending. However, where such in-plane loading conditions are compressive, cylindrical shells are likely to exhibit an unstable response characterized by localized out-of-plane deformation. Computerized numerical simulation is often required for accurate and efficient estimation of the strains and resultant stresses in cylindrical shells under loading, especially where the thickness of the shell is sufficient to evoke an inelastic buckling response in the structure. The buckling behavior of thin-walled cylindrical shells subjected to uniform axial compression has been studied in this paper using the finite element (FE) simulation method to assign respective material, geometric, loading and boundary properties to computer-generated cylindrical shell specimens. Extensive parametric analysis, consisting of approximately 720 FE runs, was then conducted based on a full-factorial empirical design, applying ample variations of the relevant parameters that influence the buckling response of axially-compressed cylindrical-shell structures. Nonlinear multiple regression techniques were then employed to derive the coefficients of nonlinear mathematical expressions, each developed as an arithmetic product of appropriate variable functions related to the respective functional sensitivities of the investigated parameters. Strain-hardening properties were incorporated into the mathematical expressions based on the shape constants of the Ndubuaku stress-strain model; which has proven to be remarkably useful for accurate parameterization of the stress-strain behavior over the full range of strains for a wide range of metallic materials, including materials with a well-defined yield plateau. Excellent predictions of FEA-derived values for the critical limit strain limit were obtained, and a simple statistical approach was presented to increase the conservativeness of the semi-empirical model as required. • A relatively superior approach for parameterizing the shape of the stress-strain curve. • Overall shape of stress-strain curve is parameterized using two model 'shape' constants. • Deformational capacity of YPT pipes is influenced by length of the yield plateau. • Critical limit strain of RHT pipes has significant relationship with PLUS ratio. • Complex interrelationships between CLS influencing parameters are adequately considered. [ABSTRACT FROM AUTHOR]

Pipelines exposed to geo-hazards such as moving slopes, discontinuous permafrost, and other ground movements may be subjected to displacement-controlled loading, which may lead to significant plastic strains. This can potentially impact pipeline structural capacity and their leak-tight integrity. Traditional stress-based design methods may become uneconomical in the design of pipelines subjected to large plastic strain. In view of the extensive use of such pipelines, reliable calibration of the tensile strain capacity (TSC) plays a critical role in strain-based design (SBD) methodology. Recent studies were focused mostly on high toughness modern pipelines with limited research performed on lower-grade vintage pipelines. However, the effects of biaxial loading due to internal pressure and bending stresses imposed on pipelines as a result of interactions with geo-hazards were not properly addressed in previous studies. This paper investigates the effect of internal pressure and flaw size on the TSC of X42 welded vintage pipelines using experimental testing. Eight full-scale pressurized four-point bending tests were conducted on 22 inches (558.8 mm) diameter X42 grade welded vintage pipes with D/t ratio of 44 to examine the effect of the influential parameters on the TSC. Biaxial strain gauges and a digital image correlation (DIC) system were major instrumentations used for measuring strain. The results were used to examine the crack growth rate by estimating the crack mouth opening displacement (CMOD) at failure and the effects of internal pressure and flaw size on the TSC. The TSC obtained from the tests were compared with those predicted using TSC predictive models proposed by ExxonMobil and Pipeline Research Council International (PRCI). [ABSTRACT FROM AUTHOR]