SUMMARYThis paper presents the calibration of an experiment based on filtration tests, able to provide the cumulative constriction size distribution of granular materials. Here, simulations of these tests are performed using a discrete element method. Filters of same density but different thicknesses are created with a poly-sized spherical material. Lateral periodic boundaries for the samples are used, and their size is calibrated so that a representative elementary volume is obtained. Fine particles are released on the created samples, and the particle size distribution of the collected material that successfully crossed the filters is computed. These particle size distributions are related to the underlying cumulative constriction size distribution (CSD) of the granular material involved in the samples. The CSD is derived using a probabilistic approach for the path length of individual particles through a granular material. We settle all the requisites related to the technique and to the fine particles that are released to allow reaching a correct CSD for the filter. The reference CSD used for the calibration of the experiment is obtained after a radical partition of the void space into Delaunay tetrahedra and a geometrical characterisation of constrictions on each tetrahedron face.

This paper presents a set of numerical simulations of different 2D boundary-value problems in order to validate a "smoothed-particle hydrodynamics"-"arbitrary Lagrangian-Eulerian" (SPH-ALE) code. This code is intended to be used to study, among other things, the problem of piping erosion in dams and dikes. The case of viscous fluid flows around a fixed cylinder was first examined. Different Reynolds numbers and different shapes for the cylinder were considered. The drag coefficient, lift coefficient, pressure coefficient, and Strouhal number were compared with previous studies from the literature. Next, a validation of the case of a Poiseuille flow between smooth pipe walls with Re = 100 was provided. The friction coefficient was computed and compared to existing analytical solutions.

Innovations in concrete technology are developing and increasing rapidly. Modifications were made in concrete research to produce concrete that is strong, economically valuable, and environmentally friendly. This can be done by using concrete waste as a concrete substitution material -which is coarse aggregate- and slag waste as a concrete substitution material for cement. In this research, the characteristic properties of these materials and the effects of their use on the strength of concrete will be studied. The compositions of Ground Granulated Blast Furnace Slag (GGBFS) varied by 0%, 25%, 50%, 75% with the coarse aggregate composition of 40% against natural aggregate. The use of 50% GGBFS gave the compressive strength of 24.8 MPa. The use of GGBFS will result the economic value of concrete and reduce CO2 emissions.

No abstract

. Landuse changing along the Bidara Cina, downstream of the Ciliwung floodplain deteriorates its environmental quality. Its interactions between the building along the floodplain and the river dynamics can be simulated with Ansys Fluent as a simulation tool. This tool simulates the impact of floods could damage the buildings structure that built in flood zones but are still within the limits of habitable zone permits. Ansys Fluent modelling is using CFD parameters, by creating geometric scenarios that have been physically tested. The geometric behavior observed through the effect of large window openings (Experiment x), namely model 1 with one window and model 2 with 2 windows, then it is analysed by rotating 0°, 30°, 45°, 60° and 90° of the building (Experiment y). The outputs that will be analyse from flood induced the building are (i) flood impact force, (ii) total force of building, and (iii) reduction of flow velocity in building. From the simulation result, it is found that building geometry with larger openings is better at resisting the impact strength of floods and reducing the velocity of flood flows. Furthermore, the graph of flood impact force and the total force of orientation in model 1 and model 2 have a tedency to increase while rotation angle increasing. We conclude that based on building type (Experiment x), the model with one window is most vulnerable model and based on building orientation (Experiment y), the model with orientation 90° is the most vulnerable model, but when viewed based on facade that is exposed to the main stream there is an opening, the orientation of 60° is the most vulnerable model.

One of the most important components in the construction execution is concrete works. Therefore, we need formworks to form the structural elements that are planned in a construction process. In the process, an economical alternative needs to be taken regarding choosing formwork material to get more benefits, both in terms of cost and time. Fabric formwork can be an alternative solution for formwork material. An example of a feasible formwork material alternative is woven polyethylene-based formwork. The purpose of this research is to evaluate the performance value of woven polyethylene formwork and compare it with the conventional formworks such as wood and brick in terms of cost and time. Field observations and literature reviews have been done to answer these questions. By using woven polyethylene formwork on tie beam and pile cap structure, it was found that the average time and the investment cost of installation are consecutively 344.23 s/m 2 and IDR75000 which is faster and cheaper than using conventional ones.

Determining building design and type of material is very important before initiating a construction project because structural design changes can impact the project’s cost and duration. This study will discuss the impacts of such changes in building design, both on structure and on cost and duration. It will focus on a case study of a showroom office building that intends to change the design of its roof from concrete to steel frames. The research will be carried out using the Finite Element Method numerical modeling, as well as cost and duration analysis. The use of steel frame may shorten the construction duration while the use of concrete roof may lower the cost.

This study shows the interaction between the solid particles with water flow occurring caused by the piping erosion phenomenon. This modelling study was executed by using Smoothed Particle Hydrodynamics (SPH) as a numerical approach with the DualSPHysics platform. The water flow is assumed as laminar flow with a low Reynolds number of 100 and 200. The solid particle is modelled as a circular-shaped particle with a fixed position. The result evaluated in this research is the coefficient of hydrodynamics force on the solid particle. In the case of interaction between one circular-shaped solid particle against the water flow, it is found that by increasing the size of volume control, the output will have higher accuracy. The accuracy of this model is also improved by elongating the maximum time simulation to ensure that the SPH particle has spread evenly throughout the volume control. In the case of interaction between two solid particles against water flow at different distances, it is found that increasing the distance between the two particles reduce the force, drag coefficient, and lift coefficient of each particle. Furthermore, the increase of distance between the two particles makes vortices form in a single dominant frequency and it affects the strouhal number.