Journal of Rehabilitation in Civil Engineering
Volume:11 Issue: 4, Autumn 2023

The HPFRCC is defined by a stress-strain response in tension, which demonstrates multiple cracking and strain-hardening behavior. This experimental study aims to investigate the splitting tensile strength (STS), compressive strength (CS), and bulk density (BD) of HPFRCC. The CS of concrete should provide an accurate basis for the STS prediction. This study consists of two phases; in the first phase, 18 HPFRCC mix proportions with 1% steel fibers (30 mm length) were formulated by taking into account the various types of aggregate distribution, water-to-cement (w/c) ratio, amount of superplasticizer, and silica fume. After testing 108 cylinder and cube specimens at 7 and 28 days, a mathematical exponential function between STS and CS was proposed with a prediction error of less than ±15%. In the second phase, in order to evaluate the effect of steel fiber volume fraction and age on the prediction equation, three distinct volume fractions of steel fibers were considered: 0%, 1%, and 2%. At the ages of 7, 28, 56, and 90 days, 144 cube and cylinder specimens were tasted. The proposed equation for HPFRCC with 1% steel fiber can be applied to specimens containing 2% fiber with an error of ±20%. Adding fibers to the cementitious mortar had a small effect on the CS. However, at 28 days, the STS for HPFRCC with 1% and 2% fibers increased by 54% and 95%, respectively, compared to specimens without fibers.

An attempt has been made in this study to correlate compressive strength, shear strength and wall stiffness for clay burnt bricks with frog mark and machine-made bricks without frog mark. In this experimental study, eight prisms and eight (254 mm) URM wall specimens with a size of 1524 mm X 914 mm were constructed with two different types of bricks, i.e., clay burnt brick with frog mark and machine-made brick without frog mark. Two types of mortar thicknesses 13 mm and 19 mm were used in the test specimens. The prism specimens were tested under axial compression normal to the bed joints and wall specimens were tested under horizontal incremental cyclic loading along with constant axial compressive load. Lateral loading was applied using a loading control pattern. The specimens were tested under cyclic loading conditions displacing them laterally, along the axis of the walls and their load-deformation behavior was measured by dial gauges. It is observed that, increasing mortar thickness prism ultimate strength increases 18.0% for clay burnt brick and with increasing mortar thickness prism ultimate strength increases 1.3% for machine made brick. On the other hand, with the increasing mortar thickness ultimate shear strength decreases 9.6% for clay burnt brick with frog mark and with increasing mortar thickness ultimate shear strength decreases 8.0% for machine made bricks without frog mark. In clay burnt brick shear strength is 12.5% more than machine made brick. Increasing mortar thickness ductility decreases 22.0% for clay burnt brick and 20.0% for machine made bricks.

Today, with the application of nanomaterials in the various branches of science and engineering fields, some researches assessed how nanoparticles affected the geotechnical characteristics of soil. Based on the collection of information from the results of previous studies, the purpose of this review article is to introduce the nanomaterials used in the geotechnical engineering and their application in the problematic soils. In this paper, the modification of the engineering properties of the clay, the sand, the collapsible soil, the soil with liquefaction potential and the soil subjected to the freeze-thaw cycles by nano materials are evaluated. The results of previous researches have shown that the nano materials can increase the resistance properties of the problematic soils. The nano materials improve the soil behavior by two mechanisms such as filling the soil voids, which increases the soil density and improves the frictional resistance of the soil as well as the improvement in the soil particles bonds, which increase in the soil integrity. The results show that the addition of nano materials to clay can lead to an average increase in strength of more than 100% and in sandy soils less than 100%. Also, the optimum content of nanomaterials for decrease in the collapsible potential was approximately 0.1%.

In this paper, aluminum beams in undamaged status and with single and double damage scenarios as slots with the ratio of the slot depth to the beam thickness of 7% and 28% were constructed at the University of Lisbon, Portugal. Then, with the help of the shrearography method, the modal rotations of each beam were calculated for the first to third vibration mode shapes. By deriving the modal rotations, the modal strains were obtained and introduced as the input of 22 different families of 2D wavelet transforms with three different scales 1, 7, and 15. Utilizing the wavelet coefficients as damage indices, the results showed that the sensitivity of modal curvatures is higher than other modal data for identifying the location of damages. In addition, among scales 1, 7, and 15, considering scale 7 for wavelet families provides more suitable results. On the other hand, the sinc and isodog wavelet families showed a better ability to reveal the damage location than other wavelets. Investigating the ratio of the maximum value of the wavelet coefficients in the middle part of the beams to the maximum value of the wavelet coefficients in the boundaries showed that among the two selected wavelets, sinc and isodog, the sinc wavelet is more sensitive than the isodog wavelet in identifying damages with obtained results of 0.81, 7.81 and 27.10 for first, second and third damage scenarios, respectively. And therefore, it can be considered the best wavelet for detecting artificial damage in the tested aluminum beams.

Structures are subjected to a variety of environmental and loading conditions over time, and minor damage to structural elements may occur. By timely identifying damage and repairing damaged locations, it is possible to prevent the spread and development of damage to other elements and, as a result, the overall destruction of the structure. This article discusses the identification and determination of the location of damage in steel plates based on the use of the primary and secondary shapes of vibration modes and the analytical method of two-dimensional wavelet analysis. Modelling and frequency analysis of the plate were performed in ABAQUS software, and the primary and secondary mode shapes were extracted. To determine the location of the damage, a damage detection index (DDI) was proposed based on the angle between the primary and secondary mode shape vectors and the diagonal detail coefficients obtained from the wavelet analysis of the primary and secondary mode shapes. The results showed that by using this index, damage can be identified by identifying peaks resulting from irregularities and disturbances. Also, the DDI value of the damage was dependent on the severity of damage occurring in a damaged situation, and the height of the disorder peaks increased with increased damage only at that damage position.

Porous asphalt (PA) are used to drain water from the surface of the asphalt pavements. It reduces aquaplaning and subsequently decreases splash and spray. Clogging reduces the permeability of PA over the years. The double layer PA are used to mitigate this problem. Different aggregate gradations and binder types can alter the performance of double layer PA. The objective of this research is to evaluate the effects of these parameters on the performance of double layer PA. For this purpose, different samples were fabricated using various aggregate gradations based on Malaysian asphalt mixture standards. Indirect tensile strength, permeability and air voids of the samples were determined. The proposed aggregate gradation for top and bottom layers were mixed with two different asphalt binders. Cantabro and binder drainage tests were later carried out on these samples. The results were then compared with the corresponding results from the Dutch double layer PA gradations. Laboratory test results showed that aggregate gradation significantly affect the indirect tensile strength, permeability and air voids of both top and bottom layer of PA. The design binder content for the bottom layer is also lower than that for the top layer. However, the binder type did not significantly change the design binder content.

The Geographic Information System (GIS) is one of the modern database software which is used to collect, analyze, display, processing and produce geographic information maps for a specific objective. In addition, a statistical analysis can be generated within GIS on specific data to produce quantitative results. In this study, the GIS utilized to produce thematic maps showing the variation of bearing capacity of shallow foundation in Al-Basrah province soil. All the features mentioned above illustrate the importance of GIS exploring more valuable results such as the bearing capacity of shallow foundation from the results of standard penetration tests (SPT) conducted in Al-Basrah province soil. The total number of boreholes drilled was 135 distributed irregularly in the study area. In each borehole, three SPTs were performed at depths of 1.5, 6, and 9.5 m measured from the existing ground level (EGL). The results of the study can be summarized by the production of thematic maps showing the variation of the bearing capacity of the soil over the whole area of Al-Basrah city correlated with several depths. These maps can be used by different local authorities to predict soil bearing capacity and choose a suitable type of foundation. In addition, it can be utilized to assess the foundations of existing and irregularly constructed buildings and to assess the extent of the risks of failure and collapse.

Composite deck slab flooring system is gaining popularity since they allow for simpler, lightweight, and more cost-effective building construction technique. The main constituent materials of a composite slab are profiled deck steel sheet and concrete. Profiled steel sheet serves two purposes it acts as a main reinforcing structural element as well as a permanent formwork during the construction phase. The efficiency of the composite slab mainly depends upon the shear interaction between concrete and steel decking sheet. This paper contributes to improving the horizontal shear strength of composite slab by utilizing basalt textile reinforced concrete (BTRC) topping. The current research is focused on examining the behavior of this shear bond action and improving its performance even without the shear connectors. Three types of concrete topping and four different shear spans (250 mm, 325 mm, 550 mm, and 625 mm) are the variables of the testing. Based on the load-displacement response, failure mechanisms, maximum strain recorded in concrete/steel, load-slip characteristics, steel-concrete shear bond resistance, and the structural performances of basalt textile-reinforced concrete (BTRC) composite slabs were compared with the conventional concrete (CC) composite slabs. BTRC composite slabs are found to be more ductile than the conventional concrete composite slab, with increased load-bearing and slip resisting capacity. Both the m–k and partial shear connection (PSC) approaches were used to calculate the horizontal shear strength of the composite floor. The m-k technique has proven to be more meticulous than the PSC method.

Based on the seismic design codes to prevent soft-story failure, columns of a soft story must be designed for amplified loads due to the discontinuity of braces or shear walls in that story. Because of the masonry infill walls discontinuity, Soft story failure has been reported in the recent earthquakes. Most national seismic design codes don't consider the effect of masonry infill walls for the design of the soft story. This paper aims to investigate the soft story failure and then present a simple formula for the design of soft-story in moment resisting frame structures. In this paper, the different arrangements of masonry infill walls are considered. Structural modeling was carried out based on reliable parameters and some national or international seismic design codes. By using nonlinear static analysis, a simple methodology is proposed and the main result is a simple formula that can be used for the engineering design of concrete moment resistant frames.