PART 1 DEALS WITH THE DYNAMIC ASPECTS OF THE SUBJECT: MATHEMATICAL ANALYSIS OF SYSTEMS SUBJECTED TO INDEPENDENT VIBRATIONS BY MEANS OF MATHEMATICAL MODELS. THE ANALYTICAL SYSTEMS USED ARE NON-LINEAR SYSTEMS, HYDRODYNAMICS AND NUMERICAL METHODS. PART 2 EXAMINES SEISMIC MOVEMENTS, THE DYNAMIC BEHAVIOUR OF STRUCTURES AND THE BASIC CONCEPTS OF THE SEISMIC DESIGN OF STRUCTURES.

Fundamentals of earthquake engineering

Loose specimens with a void ratio of 0.86, corresponding to a relative density of 30% for the pure sand, and normal stresses of 50, 100 and 150 kPa were used in this work to study strength and defo...

Strength and deformation behaviour of sand-rubber mixture

Review of concrete with expanded polystyrene (EPS): Performance and environmental aspects

This study examines the use of granular soils mixed with tire derived aggregates (TDA) as an underlying soil layer for surface foundations. The benefit of this geotechnical seismic isolation (GSI) scheme is threefold: the seismic force and displacement are significantly reduced; the construction is similar to that of a regular compacted granular fill and the re-use of scrap tires has an assertive environmental impact. These features highlight the rubber/soil mixtures (RSM) as a promising seismic isolation technique for infrastructure and large-scale structures. The seismic isolation capabilities of a rubber-soil foundation layer are investigated, using well defined material properties, and the direct analysis method of the soil-structure system, in the form of a simple oscillator on a soil profile. The influence of the RSM layer on the fundamental variables of the seismic response, namely the base shear and the total drift displacement of the structure on deformable soil, is examined. The structure’s overall stability is studied by means of monotonic lateral load analysis and incremental dynamic analysis, varying the slenderness of the structure and the synthesis of the mixture. The effectiveness and capabilities of the RSM isolation scheme are presented and discussed.

A numerical investigation on the seismic isolation potential of rubber/soil mixtures

Mechanical behavior analysis of buried polyethylene pipe under land subsidence

Combining EPS geofoam with geocell to reduce buried pipe loads and trench surface rutting

Experimental evaluation of an expanded polystyrene (EPS) block-geogrid system to protect buried pipes

With increase in cities' population and development of urbane life, passing buried pipelines near ground's surface is inevitable in urban areas, roads, subways and highways. This paper presents the results of three-dimensional full scale model tests on high-density polyethylene (HDPE) pipe with diameter of 250 mm in geocell reinforced soil, subjected to repeated loading to simulate the vehicle loads. The effect of geocell's pocket size (55*55 mm and 110*110 mm) and embedment depth of buried pipe (1.5 and 2 times pipe diameter) in improving the behaviour of buried pipes was investigated. The geocell's height of 100 mm was used in all tests. The repeated load of 800 kPa was applied on circular loading plate with diameter of 250 mm. The results show that the pipe displacement, soil surface settlement and transferred pressure on the pipe's crown has been influenced significantly upon the use of geocells. For example, the vertical diametric strain (VDS) and soil surface settlement (SSS), in a way that using a geocell with pocket size of 110*110 mm reduces by 27% and 43%, respectively, compared with the unreinforced one. Meanwhile, by increasing buried depth of pipe from 1.5D to 2D, the use of geocell of 110*110 mm delivers about 50% reduction in SSS and VDS, compared with the unreinforced soil.

https://iopscience.iop.org/article/10.1088/1755-1315/95/2/022030/pdf

Protection of Buried Pipe under Repeated Loading by Geocell Reinforcement

With growing populations and continuing urban development, embedding pipes in the ground that are then overrun by traffic is inevitable. This paper describes full-scale prototype tests on h...

/pdf/experimental-evaluation-of-geocell-and-eps-geofoam-as-means-468cuvzdeh.pdf

Experimental Evaluation of Geocell and EPS Geofoam as Means of Protecting Pipes at the Bottom of Repeatedly Loaded Trenches

This paper presents a set of results of plate load tests that imposed incremental cyclic loading to a sandy soil bed containing multiple layers of granulated rubber-soil mixture (RSM) at large model scale. Loading and unloading cycles were applied with amplitudes incrementally increasing from 140 to 700 kPa in five steps. A thickness of the RSM layer of approximately 0.4 times the footing diameter was found to deliver the minimum total and residual settlements, irrespective of the level of applied cyclic load. Both the total and residual settlements decrease with increase in the number of RSM layers, regardless of the level of applied cyclic load, but the rate of reduction in both settlements reduces with increase in the number of RSM layers. When the thickness of the RSM layer is smaller, or larger, settlements increase and, at large thicknesses may even exceed those of untreated soil. Layers of the RSM reduced the vertical stress transferred through the foundation depth by distributing the load over a wider area. With the inclusion of RSM layers, the coefficient of elastic uniform compression decreases by a factor of around 3-4. A softer response was obtained when more RSM layers were included beneath the footing damping capacity improves appreciably when the sand bed incorporates RSM layers. Numerical modeling using “FLAC-3D” confirms that multiple RSM layers will improve the performance of a foundation under heavy loading.

N. Joz Darabi

Papers

Combining EPS geofoam with geocell to reduce buried pipe loads and trench surface rutting

Experimental evaluation of an expanded polystyrene (EPS) block-geogrid system to protect buried pipes

Protection of Buried Pipe under Repeated Loading by Geocell Reinforcement

Experimental Evaluation of Geocell and EPS Geofoam as Means of Protecting Pipes at the Bottom of Repeatedly Loaded Trenches

Cyclic loading response of footing on multilayered rubber-soil mixtures