International Journal A Micro Mechanical Homogenisation
The micro-mechanical model can be implemented in any standard finite element program as a user supplied subroutine defining the mechanical behaviour of an equivalent homogenised material.
The aim of the research is to implement and validate a reliable and fast numerical tool able to represent the static and dynamic …Strengthening of masonry structures using steel frames – Masonry International Journal
The seismic behavior of masonry buildings left only with their perimeter walls and retrofitted using steel frames (a reversible technique) is investigated.
The connection of the masonry walls at the floor level with the interior structure is also beneficial to the buildings seismic behavior. In this paper, the behavior of polyurethane foams, used as adhesives for the construction of thin joints brick masonry walls, has been investigated.
The choice of the type of brick and its dimensions were the main target of the structural calculus. As a consequence, many buildings were declared nonaccessible although the structure remained apparently intact. Moreover, further studies regarding the behavior of thin joints in presence of fiber-reinforced mortars have been developed. For this kind of joints, polyurethane foams can also be used to make up a wall. All the samples were based on the concept of the “double-layered” foam-filled block. The objective of the conducted experimentation was to obtain a new lightweight plaster material with good thermal insulating properties for industrial applications. More recently, investigations have turned to assessing the influence of soil backfill on bridge behaviour. Realistic assessment of existing masonry structures requires the use of detailed nonlinear numerical descriptions with accurate model material parameters. This model, which consists of several non-linearities, is tested under non-linear time history analysis. A damage model for old masonries is presented. A repetitive unit cell is chosen and eight possible undamaged and damaged states for the masonry are identified. The generally nonmatching meshes of the distinct domains are coupled with the use of a mesh tying method.
The sample is rigidly held and a clamp is fixed to the upper part. The test consists in placing a masonry sample under a proper equipment capable of stressing the foam joint between two blocks, with a controlled increasing load up to failure.
Figure 13, the trend of the displacements as function of the applied load can be observed. The final ageing and use takes place after 3-4 days approximately. The wall specimen was instrumented with pressure gauges and strain bases placed along the diagonals. How long does it take to format my paper? I cannot find my template in your gallery, can you create it? Bokholt define the resistance function as two phases. The second phase is a decaying resistance phase that relies on the self-weight and the axial loads applied to the wall as the source of resistance.
The axial load can increase the lateral resistance above that which would be available without axial thrust; therefore, the decay phase may start where the elastic portion ends, or if the axial load is relatively low, the decay phase will start below the elastic portion.
For the elastic phase, there is no crack in the wall; therefore, y = 0. The primary differences are the peak resistance and the resistance decay after cracking. Table 1 summarizes the section parameters used in the thickness variable analyses. Moradi method results in the lowest peak resistance. The method does not consider any additional applied axial load. Three different block sizes are used: 150 mm (6 in), 200 mm (8 in), and 300 mm (12 in). Moradi method tends to predict the least deflection at ultimate resistance. Moradi method fell between the other two models in most cases. The gap width adversely affects the maximum resistance of the wall, as expected. Figure 16, the method used to generate the resistance greatly affects the response prediction. Wall 1 revealed that the corners of the support framing around the test panel were cracked, indicating that the intended arching supports did not provide the assumed perfectly rigid boundary.
Figures 19 and 20) where it can be inferred that a portion of the post-first peak rebound is due to the simultaneous negative phase.
Wall 1, however, the peak deflection occurs within the first cycle since the support frame did not crack. Blast response of lightly attached concrete masonry unit walls.
A micro mechanical homogenisation model for masonry
Each curved steel beam is supported at either end in such a way as to facilitate readily lowering of the centring. Perth penetrometer tests can also be carried out at discrete locations along the longitudinal centre line of the tank, to aid later strength characterisation.
The gauge across the mortar joint measures strain in the mortar joint and the brick. This ensures that the camera positions are identical in all tests, and cannot be accidentally altered during a test. Reference markers are also placed on the steel frame of the test chamber and on the acrylic windows at specified discrete locations. The test programme requires controlled cyclic loading as well as quasi-static loading to simulate working load and load to failure conditions, respectively.
This peak load was selected to ensure that the load would remain within the anticipated range of elastic response of the arch and is representative of a typical working axle load.
The actuators are directly connected to a longitudinal beam with a single degree of freedom connection and all five hydraulic actuators are connected to a manifold which supplies and controls the hydraulic oil movement between the pump and the actuators.
Beyond this phase displacement control was used, with readings taken once an ∼2 mm increment of displacement had been observed at the quarter-point. In the tests performed to date, the displacement rate was set to 10 mm/h up to an initial 5 mm cumulative displacement and the displacement was then maintained constant for 10 min.
This loading regime was repeated after a number of cycles of the normal speed cyclic loading regime (104, 105 and 106 cycles). The arch was subjected to a large number of cycles (e.g. To illustrate the capability of the large-scale testing facility described, tests on three full-scale bridges will be briefly reported. The servo-controlled system was used to apply the load, despite using the manual override function. The displacement rate was set to 10 mm/h. It is important to note that some damage to the latex was observed during the testing caused by soil movements within the chamber, but this did not unduly affect the performance of the image analysis.
The arch barrel was visually inspected prior to the start of every test phase. The hydraulic loading and control systems and the instrumentation generally performed well throughout the tests performed. From screening to quantitative sensitivity analysis. Damage models for the seismic response of brick masonry shear walls. Homogenised limit analysis of masonry walls. Enjoy affordable access to over 18 million articles from more than 15, 000 peer-reviewed journals. Read and print from thousands of top scholarly journals. Thus, most of the historical structures around to estimate macroscale model parameters from the mechanical the world are made of brick- or stone-masonry. The units and mortar joints can be used. Amadio), real large-scale masonry structures. The application to mesou2013model calibration was the aim of previ- – the data measured in the test. In traditional recognised that the estimation of the elastic parameters is strongly tests, this step consists of simple analytical expressions relating affected by the stress state of the test, and the presence of tensile the output of the test with the unknown parameters.
In this paper, an the post-processing involves creating a numerical model of the experimental programme in which an inverse analysis procedure is test and performing an optimisation analysis.
The discretisation for the struc- sional practice in structural engineering. Mesoscale representation for brick-masonry. Physical meaning of model parameters allowing for a possible crack in the brick. Youngu2019s mod- tic property of the material. The model parameters include: restrained. A global sensitivity analysis was performed considering the their effect can be neglected. The total number of evaluations typical value in the literature was considered. Different interface material properties were used to model head and bed joints. Results of the inverse analysis only half specimen was discretised adding appropriate symmetry constraints.
“The Fez That The Shriners Wear Is The Fez Of The Moors” ~ Minister Louis Farrakhan
“The Fez that the Shriners wear is the Fez of the MOORS” ~ Minister Louis Farrakhan.