scholarly journals Pengaruh Klasifikasi Kelas Situs Menurut SNI 1726-2019 Terhadap Keruntuhan Progresif pada Struktur Gedung Tidak Beraturan

2021 ◽  
Vol 9 (2) ◽  
pp. 123-131
Author(s):  
Raja Syarif Siregar ◽  
Zulfikar Djauhari ◽  
Ridwan

Seiring perkembangan teknologi konstruksi gedung, pembangunan gedung bertingkat dengan struktur tidak beraturan semakin bertambah demi memenuhi aspek estetika gedung maupun akibat keterbatasan lahan. Bentuk struktur tidak beraturan ini berpengaruh terhadap keruntuhan progresif gedung. Selain aspek desain, pada perencanaan gedung beban gempa harus direncanakan dengan peraturan baru yang berlaku yaitu SNI 1726-2019. Salah satu perubahan yang terjadi pada SNI 1726-2019 adalah klasifikasi kelas situs. Penelitian ini bertujuan untuk mengkaji pengaruh klasifikasi kelas situs terhadap keruntuhan progresif struktur gedung tidak beraturan. Penelitian ini dilakukan dengan menganalisis elemen struktur berupa kolom dan balok sebelum dan sesudah menghilangkan salah satu kolom struktur berpedoman pada General Services Administration (GSA) dengan beban gempa yang bekerja beban gempa statik ekivalen pada keempat klasifikasi kelas situs yaitu SB (Batuan), SC (Tanah keras), SD (Tanah sedang) dan SE (Tanah lunak). Pemeriksaan kekuatan struktur menggunakan perangkat lunak berbasis elemen hingga untuk mengetahui nilai Demand Capacity Ratio (DCR), Bending Moment Ratio (BMR) dan Robustness Indicator (R). Struktur dikatakan mengalami keruntuhan progresif apabila nilai DCR > 1,5. Dari hasil analisis diketahui nilai DCR dari kelas situs SB ke kelas situs SE mengalami kenaikan sedangkan nilai BMR mengalami penurunan. Hasil analisis juga menunjukkan bahwa keruntuhan progresif tidak terjadi pada keempat kasus kegagalan kolom dan perbedaan kelas situs terhadap gaya aksial dan momen, namun terjadi terhadap gaya geser. Nilai Robustness Indicator (R) yang didapat mendekati sama dengan satu (R≈1), nilai tersebut mengindikasikan bahwa penyaluran beban berjalan dengan normal.

Author(s):  
Shinji Konosu ◽  
Norihiko Mukaimachi

Assessment of the local thin area should be undertaken for both tension and compression bending. In this paper, simplified reference stresses for a flaw in a cylinder are proposed. By using these results, a newly-developed p-M (internal pressure ratio and external bending moment ratio) diagram which can evaluate the plastic collapse condition for pressure equipment such as vessels, piping and storage tanks with a local thin area simultaneously subjected to internal pressure, p, and external bending moment, M, due to earthquake, etc. is proposed. The p-M line is verified by comparison with the FEA results and the numerous results of experiment for a cylinder with a volumetric flaw obtained through the reference literatures. It was clarified that the differences in plastic collapse limit between the p-M line and DNV guideline under both internal pressure and compression moment became evident where the outer diameter/wall thickness of a cylinder is large and the yield ratio of the material is small.


Author(s):  
Haruna Utsunomiya ◽  
Masayuki Haraguchi ◽  
Masae Kido ◽  
Keigo Tsuda

In the design of slender steel beam-columns, the moment amplification factor is used to estimate the maximum bending moment. The formulas for evaluating the factor have been presented on the basis of the elastic or elastic-plastic analysis, however the initial deflection of beam-columns is not considered. This paper discusses the effect of initial deflection on the value of the moment amplification factor by performing the analytical work. The analytical model is a simply supported beam-column subjected to constant axial compressive force and end moments. First of all, the equilibrium differential equation which governs the problem is solved and the formula for calculating the bending moment is obtained. In the parametric study, magnitude of the initial deflection, the axial load ratio, the slenderness ratio and the end moment ratio are selected as the parameters. The effects of magnitude of the initial deflection and the end moment ratio on the moment amplification factor are discussed.


Author(s):  
Hailong Shao ◽  
Jongsoo Lee

This study proposes an optimal design of a dolphin structure under offshore load conditions such as berthing, mooring, wind, wave, and current loads. The design objective is to reduce the total weight of the pile structure by determining its diameter, thickness, and arraying direction with constraints of axial compressive pressure-bending moment ratio and total displacement. As design requirements, the stress has to be satisfied under the allowable compressive pressure-bending moment, and the total displacement of the steel piles should be less than 0.1 m on the upper deck. The structural analysis data are generated using Box–Behnken design based on the design of experiments. In the meta-model-based approximate optimization process, the pressure-bending moment ratio and total displacement are expressed using a backpropagation neural network, and the structural weight of the pile is approximated via a second-order polynomial-based response surface model. Compared with the initial design, the optimal solution of the total weight of the steel piles reduces by 27.37% under the satisfied constraint conditions. For the post-optimization study, the optimal sensitivity analysis with respect to the seabed level is conducted.


2000 ◽  
Vol 15 (6) ◽  
pp. 1094 ◽  
Author(s):  
A. Schibler ◽  
M. Schneider ◽  
U. Frey ◽  
R. Kraemer

2005 ◽  
Vol 10 (2) ◽  
pp. 151-160 ◽  
Author(s):  
J. Kala ◽  
Z. Kala

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.


1983 ◽  
Vol 11 (1) ◽  
pp. 3-19
Author(s):  
T. Akasaka ◽  
S. Yamazaki ◽  
K. Asano

Abstract The buckled wave length and the critical in-plane bending moment of laminated long composite strips of cord-reinforced rubber sheets on an elastic foundation is analyzed by Galerkin's method, with consideration of interlaminar shear deformation. An approximate formula for the wave length is given in terms of cord angle, elastic moduli of the constituent rubber and steel cord, and several structural dimensions. The calculated wave length for a 165SR13 automobile tire with steel breakers (belts) was very close to experimental results. An additional study was then conducted on the post-buckling behavior of a laminated biased composite beam on an elastic foundation. This beam is subjected to axial compression. The calculated relationship between the buckled wave rise and the compressive membrane force also agreed well with experimental results.


2020 ◽  
Vol 65 (1) ◽  
pp. 137-144
Author(s):  
Marius-Vasile Pop

This paper presents a method to find the severity of a crack for cantilever beams that can be used to estimate the frequency drop due to the crack. The severity is found for the crack located at the location where the biggest curvature (or bending moment) is achieved. Because the fixing condition does not permit a symmetrical deformation around the crack, the apparent severity is smaller as the real one. The latter is found by the estimated value of the trend-line at the fixed end, it being constructed on points that consider the crack position (equidistant points in the proximity of the fixed end) and the resulted deflections.


2018 ◽  
Vol 14 (1) ◽  
pp. 6057-6061 ◽  
Author(s):  
Padmanaban M S ◽  
J Sreerambabu

A piled raft foundation consists of a thick concrete slab reinforced with steel which covers the entire contact area of the structure, in which the raft is supported by a group of piles or a number of individual piles. Bending moment on raft, differential and average settlement, pile and raft geometries are the influencing parameters of the piled raft foundation system. In this paper, a detailed review has been carried out on the issues on the raft foundation design. Also, the existing design procedure was explained.


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