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The Halmahera Sea is part of the eastern entry route of the Indonesian throughflow (ITF) passages. The characteristics and transformation of the South Pacific water masses are presented based on the HYCOM model (Hybrid Coordinate Ocean Model) and direct observations of CTD (Conductivity, Temperature, Depth) acquired during the East Indonesian Expedition in October 2017 using RV Baruna Jaya VIII. This study is aimed at characterizing the typical water masses observed in the Halmahera Sea and tracking the transformation of the South Pacific water masses in the region. The results show that there was an indication of strong vertical mixing of maximum salinity of the South Pacific thermocline water masses, i.e., South Pacific Subtropical Water (SPSW), from ~35.2 PSU at isopycnal 24 – 25 kg m-3 becomes ~34.8 PSU in the Southern Halmahera Strait (around 200 km from the entry passage, the Northern Halmahera Strait), and rapidly decreases from the Southern Halmahera Strait and Obi Strait to become 34.6 PSU in the Maluku Sea. These preliminary findings suggest a strong mixing in the southern Halmahera Strait and Obi Strait.

Observations of past earthquakes as well as numerical and experimental studies have confirmed the acceptable performance of Steel Plate Shear Walls (SPSW). Although the SPSW has a number of advantages, it has two major flaws: low elastic-buckling capacity of the infill plate and significant stresses generated by the infill plate on the boundary columns. There are some techniques to overcome these shortcomings. Among them, using the semi-supported SPSW is the most effective one. However, the weak point of this system is the reduction of stiffness and strength of the system in comparison with the conventional SPSW. To resolve this issue, an innovative four-layer semi-supported SPSW has been introduced recently. The system is composed up of the main frame, secondary columns, two corrugated infill plates, and two flat infill plates. Since there is no connection between the infill plates and the mainframe, there is no stress transmission from plates to columns. This fact, in turn, reduces the ductility demand. As a result of the combination of the corrugated and flat plates, the buckling capacity of the wall increases nearly up to the yielding point. This results in a more cost-effective system. The current study presents the results of a comprehensive numerical study to investigate the effect of plate thickness, wall length, and aspect ratio on the behavior of this system under the monotonic lateral load. To obtain the pushover curves, the finite element (FE) software package ABAQUS was utilized. The findings showed that, as the aspect ratio of the wall increases, the wall capacity increases and exceeds the capacity of the frame. Furthermore, the relevant equations for achieving the pushover curve were proposed without the need for FE simulation. Finally, the results showed a good match between the FE results and the intended relations.

Despite the considerable advantages of SPSW, there were some shortcomings concerning the system. Needing huge columns surrounding the infill plate has been the main dilemma of the SPSW system. This problem will be due to high imposed stresses to columns by the infill plate. Perforated SPSW has shown a capable method among the proposed methods to reduce applied forces to SPSW's columns. In this paper, the optimum configuration of holes was investigated experimentally and numerically. Results indicated that the imposed forces to columns are reduced by increasing of hole area. The ultimate strength and energy absorption of perforated SPSW also are reduced by increasing of hole area. Therefore, the optimum configuration was proposed to achieve a minimum reduction in structural parameters and maximum reduction in column forces. Besides, new relations were proposed to calculate the structural parameters of the perforated SPSW. The proposed relations showed a good agreement with finite element results. [ABSTRACT FROM AUTHOR]

In this study, High Performance Steel Plate Shear Wall (HPSPSW) were properly determined using numerical and paramedical approaches. The properties of HPSPSW and LYP (Low Yield Point) steel (LHPSPSW) were measured. In so doing, 27 numerical models were analyzed and evaluated. The numerical results indicated that the SPSW has a higher stiffness, ultimate strength, and energy absorption than HPSPSW. Also, it was shown that LHPSPSW exhibits higher properties compared to SPSW and HPSPSW in both elastic and inelastic zones. It was also concluded that using LYP in HPSPSW enhances the seismic parameters of the system (stiffness, energy absorption, ultimate strength).

Steel plate-concrete shear walls (SPSW) are used as the containment in nuclear power stations. However, the influence of holes and axial loading on the behavior of steel plate-concrete shear walls is neglected in most studies. Thus, it is necessary to understand the seismic behavior of SPSW members with holes in order to avoid the potential risks for nuclear power stations. In this study, a series of specimens were tested by low-cycle reciprocal loading. The specimens were designed with different holes to simulate real members in nuclear power stations. A hysteretic curve of specimens was obtained from a low-cycle reciprocal test to discuss the seismic behavior of steel plate-concrete shear walls (SPSW). Moreover, effects of axial compression ratio, hole size, thickness of the steel plate, and hole position on the hysteretic performance of SPSW were analyzed. The horizontal ultimate bearing capacity of SPSW specimens was estimated using the norms of the Architecture Institute of Japan and the calculation method of Ono reduction rate. Results provide theoretical references for the design and application of SPSW with holes. [ABSTRACT FROM AUTHOR]

• Seismic design of the steel plate shear wall with rigid beam-column connections. • The theory of plastic mechanism control is proposed with reference to SPSW. • Presenting an accurate design procedure to achieve the global mechanism. • Seismic performance of the designed SPSWs using the nonlinear static analyses. The present study deals with the seismic design of steel plate shear walls (SPSWs) using the theory of plastic mechanism control (TPMC). The TPMC is based on the theory of kinematic rigid-plastic, which by applying the second-order effects, can prevent the development of undesirable generic mechanisms such as soft stories, and it can ensure that the structure reaches the global mechanism. The global mechanism is a mechanism in which the damage distribution is uniform, and therefore, the maximum energy dissipation in the structure can be fulfilled. The present study first presents the seismic design provisions of the SPSW and then the SPSW design algorithm using TPMC. For practical examples, three frames including three-, six-, and nine-story frames with SPSW were designed using the proposed algorithm. For validation of the design procedure, the designed frames were evaluated by means of non-linear static analysis, showing that the frames can reach the global mechanism and their excellent seismic performance. [ABSTRACT FROM AUTHOR]