scholarly journals The necessity of transverse steel reinforcement for confinement in structural reinforced concrete walls using nonlinear static and dynamic analysis method

2020 ◽  
Vol 18 (2) ◽  
pp. 161-175
Author(s):  
Eisa Mohammad ◽  
Eisa Mohammad
Keyword(s):  
Reinforced Concrete ◽  
Time History ◽  
Nonlinear Static Analysis ◽  
Concrete Walls ◽  
Static And Dynamic Analysis ◽  
Concrete Members ◽  
Reinforced Concrete Walls ◽  
Steel Bars ◽  
Nonlinear Static ◽  
Transverse Steel

Reinforced concrete walls are one of the most efficient and earthquake-resistant systems. In order to provide adequate performance against seismic forces, their ductility should be provided by considering some design principles. Since confining the concrete increases the ductility of the reinforced concrete members, design instructions try to increase the ductility of the wall by utilizing transverse rebars in a certain length of wall edges. In this study, the need for the transverse steel bars to apply confinement in concrete is compared with the equations suggested by previous studies for the displacement-based design of structural bearing walls. For this purpose, nonlinear static analysis and time history analysis was utilized. The results of the study indicate that the lateral deformation of the structural bearing walls is less than the final limit specified by the design codes, even without considering the transverse steel bars for concrete confinement.

Evaluation of Reinforced Concrete Members Damaged by Earthquakes

1996 ◽  
Vol 12 (3) ◽  
pp. 457-478 ◽  
Author(s):  
Robert D. Hanson
Keyword(s):  
Reinforced Concrete ◽  
Experimental Results ◽  
Structural System ◽  
Concrete Walls ◽  
Lateral Capacity ◽  
Concrete Members ◽  
Reinforced Concrete Walls ◽  
Crack Repair ◽  
Seismic Repair ◽  
Repair Techniques

A number of building authorities have included or are proposing to include loss in lateral capacity of the structural system caused by earthquake damage as a basis for requiring specific degrees of seismic repair and upgrades of the damaged members or of the entire structural system. Attempts have been made to apply this criteria through the size of cracks in reinforced concrete walls. This paper reviews experimental results which demonstrate that size of wall crack is not directly related to a reduction in wall capacity. The effectiveness of various wall crack repair techniques on restoring wall characteristics is discussed.

Nonlinear Static Analysis Method

2021 ◽  
pp. 285-344
Keyword(s):  
Reinforced Concrete ◽  
Time History ◽  
Nonlinear Static Analysis ◽  
Nonlinear Time History Analysis ◽  
Eurocode 8 ◽  
Test Bed ◽  
Reinforced Concrete Building ◽  
Concrete Building ◽  
Nonlinear Static ◽  
Nonlinear Time History

This chapter presents the nonlinear static methods of analyses for seismic design of structures considered by Eurocode 8. The first method is the nonlinear pushover procedure, which is based on the N2 method. The second method is the classical nonlinear time history analysis. The first method is studied in more detail, because the second method is a well-established procedure whose only drawback is the time necessary for the analyses. Nonlinear solvers and procedure in program Z_Soil are described. After a simple nonlinear SDOF application, a test-bed application consisting of an existing two-story reinforced concrete building in Bonefro, Italy is used to compare the two nonlinear procedures. The selected building is representative of typical residential building construction in Italy in the 1970s and 1980s. The aim of this chapter section is to compare 2D and 3D procedures implemented in Z_Soil software. The second example is a 14-story reinforced concrete building designed according to the Algerian code using Sap2000 software.

scholarly journals Cracked reinforced concrete walls of chimneys, silos and cooling towers as result of using formworks

2018 ◽  
Vol 146 ◽  
pp. 02002 ◽  
Author(s):  
Marek Maj ◽  
Andrzej Ubysz
Keyword(s):  
Reinforced Concrete ◽  
Concrete Cover ◽  
Cooling Towers ◽  
Concrete Walls ◽  
Reinforced Concrete Walls ◽  
Steel Bars ◽  
Live Loads ◽  
Moisture Influence ◽  
Concrete Shell ◽  
Concrete Shells

There are presented in this paper some problems connected with reinforced concrete shell objects operation in the aggressive environment and built in method of formworks. Reinforced concrete chimneys, cooling towers, silos and other shells were built for decades. Durability of cracked shells are one of the most important parameters during process of designing, construction and exploitation of shells. Some reasons of appearance of horizontal and vertical cracks as temperature, pressure of stored material, live loads e.g. dynamic character of wind, moisture, influence of construction joints, thermal insulation, chemistry active environmental etc. reduce the carrying capacity of the walls. Formworks, as is occurred recently, are the reason for technological joints with leaking connection, imperfections of flexible formworks slabs and as result can initiate cracks. Cracked surface of this constructions causes decreasing capacity and lower the state of reliability. Horizontal, vertical cracks can caused corrosion of concrete and steel bars, decreasing stiffness of contraction, increasing of deflection and carbonation of concrete cover. Local and global imperfactions of concrete shells are increasing according to greater number of cracks...

scholarly journals Displacement Demand for Nonlinear Static Analyses of Masonry Structures: Critical Review and Improved Formulations

Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 118
Author(s):  
Gabriele Guerrini ◽  
Stylianos Kallioras ◽  
Stefano Bracchi ◽  
Francesco Graziotti ◽  
Andrea Penna
Keyword(s):  
Time History ◽  
Nonlinear Static Analysis ◽  
Equivalent Linearization ◽  
Eurocode 8 ◽  
Masonry Structures ◽  
Equivalent Viscous Damping ◽  
Inelastic Displacement ◽  
N2 Method ◽  
Nonlinear Static ◽  
Nonlinear Time History

This paper discusses different formulations for calculating earthquake-induced displacement demands to be associated with nonlinear static analysis procedures for the assessment of masonry structures. Focus is placed on systems with fundamental periods between 0.1 and 0.5 s, for which the inelastic displacement amplification is usually more pronounced. The accuracy of the predictive equations is assessed based on the results from nonlinear time-history analyses, carried out on single-degree-of-freedom oscillators with hysteretic force–displacement relationships representative of masonry structures. First, the study demonstrates some limitations of two established approaches based on the equivalent linearization concept: the capacity spectrum method of the Dutch guidelines NPR 9998-18, and its version outlined in FEMA 440, both of which overpredict maximum displacements. Two codified formulations relying on inelastic displacement spectra are also evaluated, namely the N2 method of Eurocode 8 and the displacement coefficient method of ASCE 41-17: the former proves to be significantly unconservative, while the latter is affected by excessive dispersion. A non-iterative procedure, using an equivalent linear system with calibrated optimal stiffness and equivalent viscous damping, is then proposed to overcome some of the problems identified earlier. A recently developed modified N2 formulation is shown to improve accuracy while limiting the dispersion of the predictions.

scholarly journals Numerical Sensing of Plastic Hinge Regions in Concrete Beams with Hybrid (FRP and Steel) Bars

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3255 ◽  
Author(s):  
Fang Yuan ◽  
Mengcheng Chen
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Plastic Hinge ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Beams ◽  
Concrete Members ◽  
Steel Bars ◽  
Hybrid Reinforcement ◽  
Steel Hardening

Fibre-reinforced polymer (FRP)-reinforced concrete members exhibit low ductility due to the linear-elastic behaviour of FRP materials. Concrete members reinforced by hybrid FRP–steel bars can improve strength and ductility simultaneously. In this study, the plastic hinge problem of hybrid FRP–steel reinforced concrete beams was numerically assessed through finite element analysis (FEA). Firstly, a finite element model was proposed to validate the numerical method by comparing the simulation results with the test results. Then, three plastic hinge regions—the rebar yielding zone, concrete crushing zone, and curvature localisation zone—of the hybrid reinforced concrete beams were analysed in detail. Finally, the effects of the main parameters, including the beam aspect ratio, concrete grade, steel yield strength, steel reinforcement ratio, steel hardening modulus, and FRP elastic modulus on the lengths of the three plastic zones, were systematically evaluated through parametric studies. It is determined that the hybrid reinforcement ratio exerts a significant effect on the plastic hinge lengths. The larger the hybrid reinforcement ratio, the larger is the extent of the rebar yielding zone and curvature localisation zone. It is also determined that the beam aspect ratio, concrete compressive strength, and steel hardening ratio exert significant positive effects on the length of the rebar yielding zone.

Effectiveness of repairing old reinforced-concrete walls of the No. 8 lock of the Moscow Canal by prestressed anchors

1996 ◽  
Vol 30 (11) ◽  
pp. 654-663 ◽  
Author(s):  
V. N. Zhukov ◽  
S. V. Ternavskii ◽  
Yu. O. Zal'tsman ◽  
A. A. Lyubomirov
Keyword(s):  
Reinforced Concrete ◽  
Concrete Walls ◽  
Reinforced Concrete Walls

Minimum thickness of concrete members reinforced with fibre reinforced polymer bars

2001 ◽  
Vol 28 (4) ◽  
pp. 583-592 ◽  
Author(s):  
Amin Ghali ◽  
Tara Hall ◽  
William Bobey
Keyword(s):  
Reinforced Concrete ◽  
Minimum Thickness ◽  
Reinforced Polymers ◽  
Flexural Members ◽  
Steel Reinforced Concrete ◽  
Concrete Members ◽  
Reinforced Polymer ◽  
Steel Bars ◽  
Fibre Reinforced Polymer ◽  
Frp Bars

To avoid excessive deflection most design codes specify the ratio (l/h)s, the span to minimum thickness of concrete members without prestressing. Use of the values of (l/h)s specified by the codes, in selecting the thickness of members, usually yields satisfactory results when the members are reinforced with steel bars. Fibre reinforced polymer (FRP) bars have an elastic modulus lower than that of steel. As a result, the values of (l/h)s specified in codes for steel-reinforced concrete would lead to excessive deflection if adopted for FRP-reinforced concrete. In this paper, an equation is developed giving the ratio (l/h)f for use with FRP bars in terms of (l/h)s and (εs/εf), where εs and εf are the maximum strain allowed at service in steel and FRP bars, respectively. To control the width of cracks, ACI 318-99 specifies εs = 1200 × 10–6 for steel bars having a modulus of elasticity, Es, of 200 GPa and a yield strength, fy, of 400 MPa. At present, there is no value specified for εf; a value is recommended in this paper.Key words: concrete, cracking, deflection, fibre reinforced polymers, flexural members, minimum thickness.

scholarly journals Evaluation of p-delta effect in structural seismic response

2018 ◽  
Vol 162 ◽  
pp. 04019 ◽  
Author(s):  
Sardasht Sardar ◽  
Ako Hama
Keyword(s):  
Seismic Response ◽  
Pushover Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Time History ◽  
Steel Structure ◽  
Nonlinear Static Analysis ◽  
Structural Behavior ◽  
Finite Element Software ◽  
History Analysis ◽  
Nonlinear Static

Numerous recent studies have assessed the effect of P-Delta on the structures. This paper investigates the effect of P-Delta in seismic response of structures with different heights. For indicating the effect of P-Delta, nonlinear static analysis (pushover analysis) and nonlinear dynamic analysis (Time history analysis) were conducted by using finite element software. The results showing that the P-Delta has a significant impact on the structural behavior mainly on the peak amplitude of building when the height of the structures increased. In addition, comparison has been made between concrete and steel structure.

Sign in / Sign up

Export Citation Format

Share Document