International Journal of Civil Engineering

This paper aims to evaluate the impact of both regular and irregular breaking waves on elevated houses with various freeboard levels. Computational fluid dynamic (CFD) analysis was utilized, and numerical outputs were validated based on available experimental tests. The validated CFD results in terms of vertical impact forces were compared with existing empirical formulas to better understand the applicability and accuracy of current methods. Turbulence sensitivity analysis shows that buoyancy-modified $$k-\omega$$ shear stress transport ( $$\mathrm{SST})$$ model can accurately predict breaking wave characteristics in terms of the water surface elevation and surface pressures. The CFD model can predict front and bottom positive pressures for all freeboard levels as well as high bottom negative pressures and subsequent negative vertical forces for the elevated house model with zero freeboard. Regarding regular breaking waves, for the house with zero freeboard, the maximum discrepancies between the experimental and numerical results for the maximum positive and negative pressures are about 8% and 14%, respectively. Regarding irregular breaking waves, horizontal and vertical forces agree well with experimental results, in which the minimum and maximum discrepancies are − 5% and + 18% associated with forces at 1/3 significant level ( $${F}_{1/3}$$ ) and the mean level ( $${F}_{\mathrm{mean}}$$ ), respectively. However, existing empirical formulas cannot accurately predict the vertical impact forces acting on elevated buildings, which highlights the need for the development of new empirical formulas to account for uncertainty in the wave field and structural characteristics. The results of this study can not only help predict accurate horizontal and particularly vertical breaking wave loads, but the outcomes also assist in developing accurate theoretical fragility curves for elevated coastal buildings.

No recent research was found regarding mix design for coating mortars. Those that exist (older ones) have limitations in use or specific materials. They are defined for the use of a certain equipment or specific condition and cannot be applied in other regions. An appropriate mix project needs to have a process that al-lows to obtain adequate proportions of the materials taking into account the different materials and conditions at the application site. Therefore, the aim of this paper is to propose an experimental mix design method for mixed mortars to be used in wall cladding and to study two types of most common aggregates (natural or crushing) through properties from the application sites and material characteristics. The experimental program of this study consisted in characterizing the materials and conducting necessary tests to evaluate the mix design method and how the characteristics of the aggregates influence the mixing design process, as well as the mechanical properties (flexural, compressive strength and pull off strength) and durability indicators (elasticity modulus, water absorption and porosity). We verified that the characteristics of the aggregates interfere with the properties of these composites and that the proposed method was able to capture this and define adequate proportions of the materials according to the exposure conditions. The method generated more economical (less cement consumption) and more sustainable mixed coating mor-tars (reduction of cement and lime in the mixtures, especially with artificial aggregate) without compromising the limiting properties Pull Off (0.390 MPa) and Flexural Strength (2.396 MPa). We conclude that the mix design method allows to optimize the characteristics of the mixed mortars depending on the type/characteristics of the aggregate and the conditions of the application environment.

This paper presents a numerical implementation of the three-dimensional viscoelastic model to describe the behavior of asphalt mastic. Details of the numerical viscoelastic constitutive formulation implemented in a finite element code are presented and illustrated. Then, uniaxial tensile tests and torsion tests were conducted to determine the viscoelastic constitutive parameters at a temperature of 20 °C. Both the capability of the model and the accuracy of the parameter determination of the displacement-based constitutive numerical model were examined by comparing the numerical predictions with the observed laboratory tests under two basic loading paths. The presented results show that the numerical predictions exhibit a rather good agreement with the experimental results for three primary modes of bending and compression loading. Therefore, the presented numerical implementation of constitutive model may be appropriate for describing the mechanical behavior of asphalt mastic when the viscoelastic constitutive parameters became available.

In this paper, a method for the detection of concrete damage under three bending test using Wheatstone bridge concept is presented. The damage is detected by monitoring a change in voltage drop (ΔV) at the Wheatstone bridge. Good correlations between crack opening and voltage drop and between damage variable and voltage drop were observed. Results of these tests confirmed that the voltage drop increase with the increase of the damage. The voltage drop significantly increases from 0.005 to 0.340 V when the damage variable increases from 0.005 to 0.93. At this stage, specimen can be considered as completely fractured. Thus, this underlines that the self-sensing method using Wheatstone bridge as the concept of electrical resistance concrete measurement is one potential technique to detect mechanical damage. Furthermore, a special effort was put on investigation of the optimal location of electrodes, i.e. which location along the specimens is the most sensitive to the damage, and the higher sensitivity is obtained when the electrodes are close to the crack location. It has been found that the sensitivity may drop by 50% when the distance between the sensor and the notch tip increases of 400%. Finally, digital image correlation (DIC) technique is also used to investigate the crack propagation during the test and to define its correlation with Wheatstone bridge voltage drop.

This study presents the formulation of a finite-element numerical method for the analysis of shear wave dispersion out of plane SH. Also, it evaluates the seismic behavior of alluvial valleys located in a semi-infinite rigid space. This formulation is implemented in computer codes in time domain. To examine the accuracy of the program, various examples are solved and some numerical considerations in the dynamic analysis of the topographic feature are investigated by parametric studies. The results indicate that the appropriate time step in the finite-element method (FEM) is 45/1000 of the predominant period of the incident wave. The appropriate length of the element should be selected for placing at least eight nodes on the smallest wavelength. Increasing Gaussian points in integrating mass matrices in comparison with stiffness matrices is not effective in the accuracy of results. It was found that the choice of δ > 0.5 in Newmark’s integration method reduced the amplitude, but the change in the $$\alpha$$ value did not affect the results. The effect of a feature on the ground response is only noticeable if the wavelengths are comparable with the dimensions of the feature.

Stilling basins dissipate energy to form hydraulic jumps and rotational flows. Hydraulic jump and rotational current phenomenon produce pressure fluctuation at the bottom of stilling basins. In the present study, pressure fluctuations and their locations have been studied in a physical model of Namrod Dam. Results showed that fluctuations in presence of jump in the basin are high and, therefore, the fluctuation factors are, respectively, high. In positive pressure coefficient (C ), it is evident that when a jump is present, the turbulence and disturbance factors increase and, therefore, the pressure fluctuations go up, respectively. In negative pressure coefficients (C ), as is expected from positive pressure coefficients, the maximum pressure fluctuations occurred at Q/Q max = 0.47 with regard to forming a complete hydraulic jump at this discharge. Regarding available empirical equations, the thickness of slab for different hydraulic conditions was calculated and compared in one-dimensional (1D) and two-dimensional (2D) conditions. By analyzing collected data, it was observed that, results of 1D were underestimated in comparison to 2D calculations. Concrete slab thickness could be observed that fluctuations have significant effect on thicknesses. However, such calculations can provide designers with general ideas on how to better understand the conditions.

The objective of this research was to investigate the engineering properties and mix design of geopolymer mortar made using fly ash, natural zeolite and ground granulated blast furnace slag as source material and combination of sodium hydroxide and sodium silicate as alkaline activator. To study the effect of sodium hydroxide concentration on compressive strength, three different sodium hydroxide solutions (8, 10 and 12 M) were used. The ratio of sodium silicate/sodium hydroxide was varied from 1.0, 2.0 to 3.0. The test results demonstrate that the compressive strength of developed geopolymer mortar increases with increase in the concentration of sodium hydroxide solution and sodium silicate content in the activator. The average maximum compressive strength was obtained when the sodium hydroxide concentration was 12 M and sodium silicate content was 3.0. At higher alkali content, the water absorption is less due to lower void spaces. The utilization of industrial waste materials such as fly ash, ground granulated blast furnace slag and natural pozzolans such as zeolite would lead to significant economic and environmental benefits in geopolymer production.

This research study aimed to investigate the effects of combining CO2 liquid and CO2 gas on the properties of mortars, both with and without slag cement. The study involved eight different mixtures, varying in slag cement content (0% and 30%), water source (normal water (NW) or carbonated water (CW)), and water-to-binder ratios (w/b) of 0.45 and 0.55. Two curing types were employed: normal or conventional curing (NC) and 24-h CO2 curing (CC). Strength and durability measurements at 7 and 28 days as well as flowability assessments were conducted following ASTM standards. The results revealed that using CW in NC samples generally increased early strength by 2–12% at 7 days. However, this improvement did not translate into enhanced long-term strength at 28 days, as the studied mixtures experienced an average decrease between 2 and 5%. Additionally, combining CC and CW showed significant enhancements in both strength and durability for slag cement mortars. These enhancements ranged from 3 to 8% compared to the reference samples. It is worth noting that combining multiple CO2 approaches did not consistently produce a synergistic effect. Therefore, it is recommended to avoid employing more than one CO2 technology in concrete materials, especially when dealing with high w/b. These findings suggest that using CW can be beneficial when prioritizing early strength over long-term strength, such as in precast concrete plants. Furthermore, the combination of CC and CW offers the potential for producing slag cement mortars with performance comparable to those containing 100% ordinary Portland cement (OPC).

This study aims to examine the failure behaviour of damaged reinforced concrete (RC) beams retrofitted using externally bonded ultra-high-performance fibre-reinforced cementitious composites (UHPFRCCs) systems at different levels of damage levels. To overcome the sudden failure in shear at supports, one strip of UHPFRCCs was bonded on the tension face with four short strips on vertical sides covering the tension strip supports and ends of damaged RC beams. The results show that an increment in the average failure capacity over that of control beams was in the range of 24.37 to 38.39%. Moreover, the serviceability of RC beams showed a marked enhancement in failure mode, crack development and deflection capacity. 0.0% of the retrofitted beams failed in shear mode. It can be concluded that, the externally bonded UHPFRCCs technique can be used for improving the RC flexural members.