Behaviour of partially grouted hollow concrete masonry subjected to concentrated loads

2003 ◽  
Vol 30 (1) ◽  
pp. 191-202 ◽  
Author(s):  
Junyi Yi ◽  
Nigel G Shrive
Keyword(s):  
Wall Thickness ◽  
Masonry Walls ◽  
Concentrated Loads ◽  
Concentrated Load ◽  
Strength Variation ◽  
Concrete Masonry ◽  
Testing Programme ◽  
Experimental Programme ◽  
The Face ◽  
Hollow Block

An experimental programme was performed to study the behaviour of hollow concrete masonry wallettes with bond beams and vertical columns of grout subjected to concentrated loads. Forty-three wallettes were tested, with concentrated loads being applied either concentrically or eccentrically, through various-sized loading plates above the grout columns or on the bond beams above the hollow blocks. When the concentrated load was applied above the grout columns, the face shells of the hollow block units attached to the grout columns split and the columns subsequently crushed. When the load was applied on the bond beams, wallettes failed similarly to hollow masonry walls without vertical columns of grout, with web splitting and vertical cracking in line with the load, followed by face-shell spalling and (or) mortar crushing. When the eccentricity was one third of the wall thickness, failure was dominated by local spalling beneath the loading plate. The testing programme and mechanisms of failure are described, together with strength variation with increasing eccentricity, and dispersion of the concentrated load through the bond beam. General implications for the design of hollow concrete masonry with bond beams and vertical columns of grout subjected to concentrated loads are discussed.Key words: hollow concrete masonry, bond beam, grout columns, concentrated load, concentric, eccentric.

scholarly journals Design rules for hollow concrete masonry walls subjected to concentrated loads

2003 ◽  
Vol 30 (1) ◽  
pp. 203-211 ◽  
Author(s):  
Junyi Yi ◽  
Nigel G Shrive
Keyword(s):  
Experimental Studies ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Concentrated Loads ◽  
Wall Width ◽  
Concentrated Load ◽  
Design Rules ◽  
Plate Length ◽  
Concrete Masonry ◽  
Concrete Masonry Walls

Design rules are proposed for assessing the bearing strengths of hollow concrete masonry walls subjected to in-plane concentrated loads. These are derived from numerical and experimental studies of this problem. Two possible zones of failure are considered: the solid–grouted masonry directly beneath the concentrated loads, and the hollow masonry beneath the grouted portion. The important factors influencing the bearing strength are taken into account: loading eccentricity across the wall width, effective loading area, loading plate length, and loading location along the wall. An angle of 22° or slope (vertical to horizontal) of 2.5:1 is chosen for a safe estimate of the dispersion of concentrated load through the solid–grouted masonry. For partial grouting patterns, at least two courses downward should be grouted to a length compatible with the loading plate. When compared with the available numerical and experimental results, conservative estimates of ultimate strength are obtained in all cases.Key words: design rules, hollow concrete masonry wall, in-plane concentrated load, out-of-plane eccentricities, loading plate length, loading locations, dispersion angle.

Behaviour of hollow concrete masonry walls with one-course bond beams subjected to concentric and eccentric concentrated loading

2003 ◽  
Vol 30 (1) ◽  
pp. 181-190 ◽  
Author(s):  
Junyi Yi ◽  
Nigel G Shrive
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Three Dimensional ◽  
Masonry Walls ◽  
Finite Element Models ◽  
Concentrated Load ◽  
Concrete Masonry ◽  
Out Of Plane ◽  
Concentrated Loading ◽  
Concrete Masonry Walls

Three-dimensional finite element models of unreinforced hollow concrete masonry walls with one-course bond beams subjected to concentrated loading have been analyzed. The walls were modelled with different loading plate sizes, different loading locations along the wall (at the midpoint of the wall, at the end of the wall, and between these points), and different out-of-plane eccentricities (e = 0, t/6, and t/3). The hollow block units, mortar, grout, and bond beam blocks in the walls were modelled separately. Both smeared and discrete cracking methods have been utilized for predicting cracking under load. Geometric and material nonlinearities and damage due to progressive cracking were taken into account in the analyses. The predicted failure modes and ultimate capacities of the walls with the concentric concentrated load applied at the midpoint or at the end of the wall compared very well with the experimental results. When the load was between the midpoint and the end of the wall, the predicted ultimate capacity was between those for the load at the midpoint and at the end. The strength of the walls decreases with increasing out-of-plane eccentricities.Key words: finite element models, hollow masonry, smeared and discrete cracking models, concentrated load, loading locations, out-of-plane eccentricities.

Numerical analysis of face-shell bedded hollow masonry walls subject to concentrated loads

1995 ◽  
Vol 22 (4) ◽  
pp. 802-818 ◽  
Author(s):  
Ezzeldin Y. Sayed-Ahmed ◽  
Nigel G. Shrive
Keyword(s):  
Finite Element ◽  
Rational Design ◽  
Element Model ◽  
Masonry Walls ◽  
Concentrated Loads ◽  
Concentrated Load ◽  
Finite Element Program ◽  
Strength Enhancement ◽  
Element Program ◽  
Iterative Procedures

A nonlinear elastoplastic finite element model has been developed for face-shell bedded hollow masonry walls subject to in-plane concentrated loads. The model takes into account geometric and material nonlinearities as well as damage due to progressive cracking. Behaviour of the masonry components subject to compressive states of stress is modelled using the theory of plasticity, and cracking is modelled using both discrete and smeared cracking approaches. The model is generated on a SUN SPARC 10/31 workstation using the preprocessor of the finite element program ANSYS; the finite element solution is obtained using the ABAQUS program on the Fujitsu VPX 240/10 and IBM RS/6000 workstation. A brief summary of the numerical modelling and the iterative procedures is discussed. Results from simulated tests of seven-course high wallettes subject to concentrated loads are used to verify the behaviour of the numerical analyses. The methodology, when combined with substructuring, allows analysis of substantially larger walls than would more typical 3-D analyses. The model can be used to check existing design rules and develop more rational design methods for hollow masonry subject to concentrated load. Key words: masonry, hollow concrete masonry, finite element modelling, cracking, failure, strength enhancement factor, concentrated loads.

Design of face-shell bedded hollow masonry subject to concentrated loads

1996 ◽  
Vol 23 (1) ◽  
pp. 98-106 ◽  
Author(s):  
Ezzeldin Y. Sayed-Ahmed ◽  
Nigel G. Shrive
Keyword(s):  
Finite Element ◽  
Load Capacity ◽  
Three Dimensional ◽  
Element Model ◽  
Concentrated Loads ◽  
Concentrated Load ◽  
Strength Enhancement ◽  
Design Detail ◽  
Current Design ◽  
The Face

Many parameters affect the behaviour and failure of face-shell bedded hollow masonry subject to concentrated load. Detailed study of these parameters is needed to develop realistic design rules for this situation. The effects of loaded length and wall dimensions on capacity of the face-shell bedded hollow masonry subject to concentrated load are studied; the effect of mortar joint strength is also evaluated. The current design detail of filling some of the blocks under the concentrated load with grout is reviewed. The study was performed with a nonlinear elastoplastic finite element model that takes into account geometric and material nonlinearities as well as damage due to progressive cracking. The methodology, when combined with substructuring, allows analysis of substantially larger walls than would more typical three-dimensional analyses. The results indicate that the length of the loading plate is the significant parameter for load capacity. A possible design equation for plain hollow masonry subject to concentrated loads, concentric across the width of the wall, is provided. Adjustments could be made given the precise loading detail specified. Improvement details are explained. Key words: masonry, hollow concrete masonry, finite element modelling, cracking, failure, strength-enhancement factor, concentrated loads.

In-plane flexural strength of unbonded post-tensioned concrete masonry walls

2017 ◽  
Vol 136 ◽  
pp. 245-260 ◽  
Author(s):  
Reza Hassanli ◽  
Mohamed A. ElGawady ◽  
Julie E. Mills
Keyword(s):  
Flexural Strength ◽  
Masonry Walls ◽  
Concrete Masonry ◽  
Concrete Masonry Walls ◽  
Post Tensioned

scholarly journals Strengthening of Reinforced Concrete Beams Subjected to Concentrated Loads

2022 ◽  
Author(s):  
Paolo Foraboschi
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Reinforced Concrete Structure ◽  
Concentrated Loads ◽  
Concentrated Load ◽  
Load Carrying

Renovation, restoration, remodeling, refurbishment, and retrofitting of build-ings often imply modifying the behavior of the structural system. Modification sometimes includes applying forces (i.e., concentrated loads) to beams that before were subjected to distributed loads only. For a reinforced concrete structure, the new condition causes a beam to bear a concentrated load with the crack pattern that was produced by the distributed loads that acted in the past. If the concentrated load is applied at or near the beam’s midspan, the new shear demand reaches the maximum around the midspan. But around the midspan, the cracks are vertical or quasi-vertical, and no inclined bar is present. So, the actual shear capacity around the midspan not only is low, but also can be substantially lower than the new demand. In order to bring the beam capacity up to the demand, fiber-reinforced-polymer composites can be used. This paper presents a design method to increase the concentrated load-carrying capacity of reinforced concrete beams whose load distribution has to be changed from distributed to concentrated, and an analytical model to pre-dict the concentrated load-carrying capacity of a beam in the strengthened state.

Design of Laterally Loaded Plating—Concentrated Loads

1983 ◽  
Vol 27 (04) ◽  
pp. 252-264
Author(s):  
Owen Hughes
Keyword(s):  
Experimental Data ◽  
Load Parameter ◽  
Uniform Pressure ◽  
Concentrated Loads ◽  
Rigid Plastic ◽  
Concentrated Load ◽  
Load Effect ◽  
Permanent Set ◽  
Multiple Location ◽  
Single Location

In the design of plating subject to lateral loading, the principal load effect to be considered is the amount of permanent set, that is, the maximum permanent deflection in the center of each panel of plating bounded by the stiffeners and the crossbeams. The present paper is complementary to a previous paper [1]2 which dealt with uniform pressure loads. It first shows that for design purposes there are two types of concentrated loads, depending on the number of different locations in which they can occur; single location or multiple location. The hypothesis is then made that for multiple-location loads the eventual and stationary pattern of plasticity which is developed in the plating is very similar to that for uniform pressure loads, and hence the value of permanent set may be obtained by using the same formula as for uniform pressure loads, with a load parameter Q that is some multiple r of the load parameter for the concentrated load: 0 = rQP. The value of r is a function of the degree of concentration of the load and is almost independent of plate slenderness and aspect ratio. The general mathematical character of this function is established from first principles and from an analysis of the permanent set caused by a multiple-location point load acting on a long plate. The results of this theoretical analysis provide good support for the hypothesis, as do also the relatively limited experimental data which are available. The theory and the experimental data are combined to obtain a simple mathematical expression for r. A more precise expression can be obtained after further experiments have been performed with more highly concentrated loads. Single-location loads produce a different pattern of plasticity and require a different approach. A suitable design formula is developed herein by performing regression analysis on the data from a set of experiments performed with such loads. Both methods presented herein, one for multiple-location loads and the other for single-location loads, are valid for small and moderate values of permanent set and can be used for all static and quasistatic loads. Dynamic loads and applications involving large amounts of permanent set require formulas based on rigid-plastic theory. Such formulas are available for uniform pressure loads and were quoted in reference [1]. A formula for single-location loads has recently been derived by Kling [4] and is quoted herein.

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