Global stability design method of buckling-restrained braces considering end bending moment transfer: Discussion on pinned connections with collars

2013 ◽  
Vol 49 ◽  
pp. 947-962 ◽  
Author(s):  
Junxian Zhao ◽  
Bin Wu ◽  
Jinping Ou
2018 ◽  
Vol 11 (1) ◽  
pp. 163 ◽  
Author(s):  
Hyunjin Ju ◽  
Sun-Jin Han ◽  
Hyo-Eun Joo ◽  
Hae-Chang Cho ◽  
Kang Kim ◽  
...  

The optimized-section precast slab (OPS) is a half precast concrete (PC) slab that highlights structural aesthetics while reducing the quantity of materials by means of an efficient cross-sectional configuration considering the distribution of a bending moment. However, since a tapered cross section where the locations of the top and bottom flanges change is formed at the end of the member, stress concentration occurs near the tapered cross section because of the shear force and thus the surrounding region of the tapered cross section may become unintentionally vulnerable. Therefore, in this study, experimental and numerical research was carried out to examine the shear behaviour characteristics and performance of the OPS with a tapered cross section. Shear tests were conducted on a total of eight OPS specimens, with the inclination angle of the tapered cross section, the presence of topping concrete and the amount of shear reinforcement as the main test variables and a reasonable shear-design method for the OPS members was proposed by means of a detailed analysis based on design code and finite-element analysis.


2011 ◽  
Vol 261-263 ◽  
pp. 1578-1583
Author(s):  
Yong Le Li ◽  
Jiang Feng Wang ◽  
Qian Wang ◽  
Kun Yang

based on the finite element method of superstructure-the pile raft foundation-the foundation soil action and interaction are studied. Research shows that the common function is considered, fundamental overall settlement and differential settlement with the increase of floor of a nonlinear trend. The influence of superstructure form is bigger for raft stress, the upper structure existing in secondary stress, and the bending moment and axial force than conventional design method slants big; With the increase of the floors, pile load sharing ratio is reduced gradually,but soil load sharing ratio is increased. Along with the increase of the upper structure stiffness, the load focused on corner and side pile; Increasing thickness of raft, can reduce the certain differential settlement and foundation average settlement, thus reducing the upper structure of secondary stress and improving of foundation soil load sharing ratio, at the same time the distribution of counterforce on the pile head is more uneven under raft, thus requiring more uneven from raft stress, considering the piles under raft and the stress of soils to comprehensive determines a reasonable raft thickness, which makes the design safety economy. As the foundation soil modulus of deformation of foundation soil improvement, sharing the upper loads increases, counterforce on the pile head incline to average, raft maximum bending moment decrease gradually.


Author(s):  
Zhao Wang ◽  
Wei Qin ◽  
Xiaojie Zhang ◽  
Jiannan Zhao ◽  
Yong Bai

Abstract The steel lazy wave riser has been used in deep-water oil and gas field development because it has good adaption to the movement of the upper platform and economic efficiency. The typical design criterion and design flow of steel lazy wave riser are introduced in this paper. The design method and the equivalence principle of distributed buoyancy modules are given. The formulas of equivalent hydrodynamic parameters are derived in this paper. The influences of distributed buoyancy modules (DBM) and the buoyancy factor on the configuration of the riser, the top tension, and the bending moment distribution are discussed and summarized. The distribution law of effective stress response along the pipe can be analyzed by dynamic analysis, and it provides reference for the global design of steel lazy wave riser.


2019 ◽  
Vol 15 (10) ◽  
pp. 155014771988135
Author(s):  
Yanchao Yue ◽  
Tangbing Chen ◽  
Yongtao Bai ◽  
Xiaoming Lu ◽  
Yan Wang ◽  
...  

Buckling-restrained braces play a critical role as the first-defendant line in dissipating seismic energy and are often used in concrete frame structures to ensure that the main beam–column members are “undamaged” or significantly elastic during medium earthquakes. The design of the reinforced concrete frame structures with buckling-restrained brace is generally based on the assumption of shear deformation of the structure. The conventional seismic design considers the “second-defendant line design” based on the geometric relationship between the axial deformation and strength of buckling-restrained braces and stratified deformation. This article proposes iterative optimization of the buckling-restrained brace design method and layout scheme based on the nonlinear structural response of the calibrated numerical model, and then approximates the nonlinear structure scheme using a linear method. Time history analyses are performed to prove that the linear design method is highly conservative for estimating seismic intensity, and the proposed design method provides more efficient damage distributions in frame components. The results of the nonlinear performance evaluation and energy analysis indicate that the method proposed in this article can meet the performance design requirements achieving multi-performance criteria.


Author(s):  
Fumio Ando ◽  
Toshiyuki Sawa ◽  
Masatoshi Ikeda

A design method of piping components for Level 2 earthquake (the possible strongest earthquake with extremely low probability of occurrence) such as bolted flanged joints, expansion joints, and equipment nozzles is described. This design method is provided taking into account their failure modes and degree of safety. The failure modes for each piping component is classified according to the past damage experience due to earthquake, and each criterion is provided against the failure mode. The typical failure modes are gas leakage, fatigue failure, cumulative plastic deformation during and after earthquake for bolted flanged joints, expansion joints and equipment nozzles in piping components, respectively. Specifically, the simplified method of bolted flanged joints is proposed as the convenient design method for chemical plants and petroleum refineries, etc. (here in after calls as plant) The method is derived using gasket factor, gasket dimensions and clamping forces due to bolts for external piping load. This practical method is investigated and verified due to the experimental results on the welding neck type flanges subjected to static bending moment, in which the bolted flanged joints of NPS 4″ and 8″ in size, 3 types of gaskets are used. In addition, the dynamic inertia force effect is also studied by the shaking table tests using cantilever model of bolted flanged joints at fixed side with changing the bolt clamping forces and gasket types.


1983 ◽  
Vol 10 (3) ◽  
pp. 337-349 ◽  
Author(s):  
B. Stafford Smith ◽  
L. Pradolin

This paper describes a design method for structures consisting of a vertically loaded masonry wall supported by a reinforced concrete beam, taking account of the composite tied-arch action of the wall and beam. Experimental results have shown that the behaviour of walls on reinforced concrete beams is similar enough to that of walls on steel beams to allow the development of a design procedure for the former using similar principles to that for walls on steel beams. Therefore, the design approach is based on the assumption of triangular distributions of vertical stress at the wall–beam interface, where the length of the distributions are a function of the beam-to-wall relative stiffness. In the design method the beam flexural stiffness is designed to give an adequate distribution of the interface stress so that the maximum stress in the wall does not exceed allowable limits. The beam is also designed with flexural and shear reinforcement sufficient to resist the bending moment, tie force, and shear forces applied by the normal and shear interface loading. Experimental evidence as well as analytical results are cited to support the assumptions and the resulting design method.


2018 ◽  
Vol 763 ◽  
pp. 916-923
Author(s):  
Ben Sitler ◽  
Toru Takeuchi ◽  
Ryota Matsui

Buckling-restrained braces (BRBs) achieve large peak and cumulative ductility capacities by restricting yielding to an encased core, while maintaining global stability. However, stability is often governed by the connections and is sensitive to the end fixity provided by the adjacent framing and gusset, and flexural continuity between the neck and restrainer. This paper presents simple analytical methods to determine the flexural properties of these key components. Full-depth gusset stiffeners are found to be highly effective in increasing the out-of-plane rotational stiffness (KRg), equivalent to doubling the thickness. An equivalent connection is proposed to account for the adjacent framing (KRf), but this may be neglected if KRf > 10∙KRg. This is typically satisfied if a diaphragm slab and transverse beam are provided, but may exceed beam torsional bracing requirements. The restrainer end moment transfer capacity is extended to mortar-filled RHS restrainers, confirming that neck insert ratios of Lin/Bn > 2.0 are required for full continuity.


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