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In order to ascertain how explosive load influences orthotropic slabs with short span stiffeners partially positioned in the x-direction, the purpose of this study is to perform a numerical analysis. The maximum displacement of a floor surface with respect to the force of an explosive load and the angle of inclination. It is feasible to calculate the impact of the angle of inclination and the height of the blast load on the vertical deflection of the slab using the 6th order polynomial blast equation, as long as the local blast load is positioned in the center of the slab. An analysis reveals that the vertical deflection of the slab is affected by the timing of the explosion. Specifically, a more powerful explosion has a diminishing effect on the deflection of the slab. The inclination angle has no major impact on the outcomes of deflection.

The purpose of this study is to analyze numerically the effect of explosions on orthotropic slabs which have partial fixity placement and stiffeners in the x direction, namely in the short span direction. The modified blast load dynamic behavior is from Reed’s equation with 4th order polynomial on orthotropic plates with x-direction stiffener. The localized blast load centered in the middle of the strain, and the effects of thickness and stiffening on the vertical deflection of the plates are solved numerically using two auxiliary equations in the x and y-directions. It is found that there is vertical deflection with related to time.

The slenderness ratio, length to diameter, of the cylindrical concrete samples of the slab block by the core-drilling method is believed to affect the compressive strength other than the aggregates in the concrete. In this study, the relationship between the compressive strength with mixing and slenderness ratio of cylindrical concrete specimens was investigated by statistics. Further, the discrimination model for mixing cylindrical concrete specimens has been developed by using machine learning algorithms, including support vector machine (SVM), linear discriminant analysis (LDA), k-nearest neighbor (k-NN), and random forest (RF). A total of 180 cylindrical concrete specimens have been measured for compressive strength using UTM. The sample consisted of a mixture of type-A and type-B with a slenderness ratio of 2.48, 2.72, and 3.28, respectively. Samples were obtained by the core-drilling method from slab block concrete. The ANOVA tests showed that the aggregate and slenderness ratio caused a significant difference in the compressive strength of the concrete (p<0.05). This indicates that the type of aggregate mixture in concrete and the slenderness ratio of cylindrical concrete specimens significantly affect the compressive strength of the concrete. The model for discrimination of mixing cylindrical concrete specimens using machine learning algorithms can be used with satisfactory results. LDA is a machine learning algorithm that can show stability in the training and testing stages with accuracy reaching 78% and inconsistency of less than 2.63% (the smallest compared to others). The descending order of machine learning algorithms based on their consistency is LDA > RF > SVM > k-NN. Subsequently, this model can discriminate the aggregate mixture on cylindrical concrete specimens obtained from the core-drilling method. [ABSTRACT FROM AUTHOR]

The Educational and Cultural Complex Area Waterway is located in Pasar Minggu District. There is connecting Waterway (PHB Pulo), which floods every rainy season. It is due to the non-technical cross-section of the waterway, sedimentation, and garbage on the west side. The obstructed flow direction is found in the elegant Pejaten housing, where the high water level of PHB Pulo causes the water to slow down. From the above conditions, it is necessary to normalize the cross-section of 1 x 1 m² using concrete / u-ditch to accommodate five-year rainfall of 2,305 m³/second, with a pump capacity to accelerate the flow to PHB Pulo by 1 m3/second. [ABSTRACT FROM AUTHOR]

Bridge maintenance is structural repair work so that it is always in good condition to serve goods and services transportation traffic. There are three levels of maintenance: routine, periodic, and rehabilitation. Effective treatment depends on the scale of the damage, starting from 0 (Excellent), 1, 2, 3, 4, and 5 (Very Bad). So it is crucial to create a reference model for changes from 0 - 5. Floor elements, as the primary function of bridge services, are damaged faster, so the type of maintenance should be precise. Research shows that the age of destruction varies from 2 to 45 years. The researchers make the model for 220 bridges, with construction age, traffic load, concrete quality, and others as independent variables. SPSS processing produces the expected model curve. Multiple linear regression analysis points non-linear curve consisting of the dominant factors causing the damage, while the ordinal logistic regression makes an integer scale. The model demonstrates a 5-scale collapse, which occurred around 54 years, and others. So, this prediction is the right program for handling with optimum financing. [ABSTRACT FROM AUTHOR]

A numerical simulation of a moving vehicle on the rigid roadway pavement with discontinuities is presented in this paper by using the data from one of the toll road segments in Indonesia. The analysis procedure considers the dynamic interaction between the vehicle and the rigid pavement. The rigid roadway pavement is modeled using the Kirchhoff theory of thin slab on elastic foundations. The aim of the numerical analysis is to obtain the vertical deflection in the middle of the slab, to obtain the time history of the slab deflection; and to identify the parameters of the sub-grade that has a significant effect on the dynamic response of the rigid roadway pavement. The equations of motion are derived in the form of partial differential equations of the fourth order. The mode shapes of the slab deflection are determined from the method of first and the second auxiliary equations of Levy-type in the x- and y-directions, which is also known as the Modified Bolotin Method (MBM). The equations of motion are solved numerically by using Mathematica. The influence of various parameters including the peak vertical velocity due to the moving vehicle, the stiffness of subgrade, the slab thickness and the road profile to the dynamic behavior of the rigid roadway pavement are studied in detail. The results obtained from the plate computing model in this paper are then compared and analyzed with the results computed using the finite element method by Strand 7 to show that the solution obtained using the MBM method is accurate. In addition, the paper aims to show that the thickness of the plate plays a significant role in the distribution of the bending stresses in plate discontinuities and is necessary for engineers to design rigid roadway pavements. [ABSTRACT FROM AUTHOR]

The exact solution of structural dynamic related problems can be achieved by using the frequency-dependent spectral method. The exact solution is thought to be accurate while reducing the number of degree-of-freedom to resolve the cost and computational drawbacks. This paper investigates the vibrational characteristics of a Levy-type solution of thick plates considering shear deformation based on the two-variable Refined Plate Theory (RPT). The plates, which are modeled by an isotropic Levy-type rectangular plate, were solved by using the Spectral Element Method (SEM). The SEM for RPT Levy-type in the frequency domain is derived to formulate the free vibration problems of the plates. Transcendental stiffness matrices are well established in vibration, formulated from the exact solutions of the differential equations of the RPT Levy-type plate element. The present spectral element model has four line-type degree-of-freedoms (DOF) on each edge of the Levy-type rectangular plate. Natural frequencies of the plate are computed by means of the Wittrick-Williams algorithm. Numerical comparisons are given to show the effectiveness, efficiency, and accuracy of the SEM by using one element. Unlike the FEM, the SEM gives exact solutions of the natural frequencies of plates without element discretization procedures. [ABSTRACT FROM AUTHOR]