Sustainability Analysis of Improvement of Contaminated Clayey Soil Using Lime Piles Technique

This study aims to use the concept of sustainability and provide guidance to geotechnical engineers to contribute towards greater sustainability in geotechnical design and construction. The methodology of the sustainability framework aims to support indicators and tools used in the sustainability concept in geotechnical engineering. In addition, available indicators will be used to analyze the role of natural resources, social impacts, environmental and economic aspects. In order to demonstrate the sustainability assessment approach, a case study is evaluated using the methodology of sustainability framework by using Multi-Criteria Analysis (MCA). The assessment is studied for raft footing and deep foundations (driven and bored piles A foundation treatment of 15×15 m and 0.45 m thickness to carry a high static load or to carry cyclic loading is analyzed. The results indicate the calculations of sustainability indices from the multicriteria analysis show that the option of raft footing than deep foundation if raft provides adequate allowable load by improving the soil using lime piles technique is sustainable.

Allowable Load Assessment in Metal-Composite Double-Lap Joint / Avaliação de Carga Permitida em Junta de Dupla Folga Metal-Composto

This work consists of evaluating the tensile and compression static allowable stress of a hybrid (metal-composite) riveted joint. The analyzed joint is composed by two sheets of 2014 – T6 aluminium alloy and a T300/5208 Graphite/Epoxy quasi-isotropic laminate, which were joined by twelve Lockbolt Swaged Collar rivets titanium alloy Ti–6Al–4V annealed. The joint was analyzed through a computational model developed using the Finite Element Method (FEM), with the fasteners modelled through the Multi - Springs technique. This method was widely used to simulate the mechanical behaviour metal-metal and composite-composite parts of the joint. It is validated comparing its results with analytical results of metallic joints available in the literature. Through this model, both the allowable load and its distribution in the fasteners of the joint were determined. Since the evaluated joint is subjected to double shear and, therefore, has no eccentricities, the presence of secondary bending was not observed, the bearing and bypass loads were the most relevant in evaluating the allowable loads of the joint. The load distribution in the joint and its components’ safety margin was determined, with the laminate being the limiting component of the allowable load.

ANALYSIS OF STRENGTH CRITERIA IN THE DESIGN OF PRODUCTS FROM COMPOSITE MATERIALS

Technological progress gives rise to the continuous expansion of the class of structural materials and the improvement of their properties. The appearance of new materials is due to the natural desire to increase the efficiency of the structures under development. One of the most striking manifestations of progress in the development of materials, structures and technology is associated with the development and application of composite materials. Composites have a number of obvious advantages over other materials, in particular over metals. Such advantages are high specific strength and rigidity, high corrosion resistance, good ability to withstand alternating loads and others. It should be noted another, perhaps the most important feature of composites - is the ability to change the properties of the material in accordance with the purpose of the structure and the nature of its load during operation. Under the influence of loads on the structure, its strength is estimated by the ultimate state of the materials of the structural elements. When a boundary state arises in a material, its transition to another mechanical state - elastic, plastic, or fracture state - occurs. This article aims to determine the optimal criterion for the strength of composite material that takes into account different values of ultimate stresses not only in different directions of the coordinate axes, but also to stretch and compress and further calculate the maximum allowable load for single-layer unidirectional composite material During the research the main properties of composite materials, methods of manufacturing parts from composite material, their main properties and methods of destruction were considered. The characteristics of the strength criteria of composite materials are given, the most suitable for calculating the maximum value of the allowable load for a single-layer unidirectional composite material is determined. The proposed approach to the optimal design of elements of single-layer composite structures may be of interest to developers of numerous and analytical methods for solving problems of optimal design of more complex structures.

Geotechnical Investigations of an Earth-Filled Site for Construction of a Building

There is a growing need of construction around the globe. This need tends to provide newer opportunities for construction of buildings over reclaimed lands or earth filled areas. Mostly, the earth is filled with soils as it is an easily available material. Soil is a complex materials, and its properties can vary due to several reasons. If not understood properly, it can damage undisturbed samples collected from earth-filled soils. The basic properties of soils, the stress-strain behavior and strength parameters are presented and discussed. Results show that soil exhibits strain hardening and normally consolidated behavior in direct shear and oedometer test respectively. It is observed that the compression index values are in the range of 0.157 to 0.182 which indicates that the material is silty soils with low plasticity. The allowable bearing capacity in our study was 305 kPa and allowable load on footing was 987 kN. The strength parameters, i.e., friction angle and cohesion are 37 degree and 2 kPa respectively.

Express plotting of model deformation curve based on wave analysis data

The paper presents the study results of the currently used nondestructive technique of multichannel analysis of surface waves which is adapted for express assessment of physical and mechanical parameters of dispersive soils during preliminary geotechnical investigation of the construction site. The authors propose a methodology for express plotting of model deformation curve of dispersive soil based on the wave analysis data, which will allow a rapid and non-expensive estimation of allowable load intervals and deformations under these loads with preliminary geotechnical assessment of foundation bases. The plotted deformation curve will be useful for obtaining initial data for numerical modeling of interaction of foundation base with the structure designed for the model of hardening soil and the model of hardening soil at small strains.

Evaluation of dynamic bending moment of disconnected piled raft via centrifuge tests

When connected piles are used as settlement reducers, the proportion of vertical load carried by the pile may come close to the allowable load of the pile. To reduce not only the vertical load, but also the lateral load and bending moment to which the pile is subjected, the disconnected piled raft (DPR) has been introduced as an effective design for the role of the settlement reducers. Although several DPRs have been constructed, most of the research efforts on DPRs are limited to the structural behavior such as the evaluation of the seismic acceleration of the structure on the DPR; thus, there is a need to evaluate the dynamic performance of DPRs focusing on geotechnical problems. In this study, the seismic behavior of DPRs is investigated using dynamic centrifuge tests and compared with the results obtained from connected piled rafts (CPRs). The bending moment of piles of different materials, namely aluminum and steel, is evaluated. Results show that there is a reduction in the amplitude of acceleration of the foundation horizontal motion for the DPR compared to the CPR. The edge pile of a DPR attracts the smaller dynamic bending moment of the pile compared to that of a CPR. The dynamic bending moment of piles is predominantly governed by the soil behavior rather than the pile material. Finally, the seismic behavior of DPR was evaluated comprehensively through centrifuge tests.

Reinforcing the Octagonal Web Openings of Castellated Beam by Steel Rings

Castellated steel beams are section steel members with hexagonal or octagonal web openings which they are made from standard hot rolled steel section I or H. The main advantage of these members is their economic material. An additional important advantage is a possibility to guide service ducts through the openings. The presence of the web openings influences the members’ failure behavior around the openings, new local failure modes will come into existence, such as the buckling of the web post between the openings, or yielding around the openings. Castellated beams with octagonal openings usually fail due to web post-buckling because of the increase in depth. The current study focused on improving the behavior of the castellated beam with octagonal openings using steel ring stiffener and adjusting the best dimension and distribution for the stiffeners. All the models of specimens have been fabricated from a parent I section (IPE 140). The models have been modeled and analyzed using finite element software ANSYS (version 15). The analysis results showed that reinforcing octagonal castellated beams by adding steel ring stiffeners around octagonal web opening was very active way to increase the ultimate load for long span, where the ultimate load of reinforced octagonal castellated beam increased up to (286%) compared with parent I-section beam. Economically, the percentage of additional steel material which used to expansion and reinforce the castellated beams (spacer plate and steel ring stiffeners) was (36%) when compared with the weight of parent I-section beam. While the allowable load at deflection (L/180) was (260 %) compared to the allowable load of parent section at the same deflection. The gained benefit was increasing the ultimate and allowable load of reinforced octagonal castellated beams by (186%) and (160%) respectively by using additional steel material only (36%) from the weight of parent I- section, which the additional steel material consisted from the spacer plates and steel rings. Also, the results indicate that the best dimensions for the ring were when thickness equal to the web thickness of the parent section and the width equal to the half of the parent section flange width.

Terra Cotta Flat Arches: A Historic Modern-Day Challenge

<p>At the turn of the 20th century, terra cotta flat arches (TCFA’s) were a popular floor system in steel framed buildings for industrial and office construction in the United States. These arches were lighter but just as fireproof as standard brick arches, and were designed empirically using proprietary allowable load tables, which were based mostly on load testing.</p><p>In the 21st century, the proprietary nature of the TCFA makes evaluating these systems problematic for the modern engineer, architect, and contractor. Renovations of buildings with TCFA floor assemblies typically will have new penetrations as well as altered loading conditions from its original construction.</p><p>It is important for all parties involved in the design and construction process of a renovation to understand the history, mechanisms, and limitations of TCFAs in order to have a successful renovation from both a design and a cost perspective. Conversely, renovating a building without the proper knowledge or experience with the existing materials can lead to change orders, time overruns, and most importantly life safety risks.</p><p>This paper is a summary of a presentation given by the same author to the Association for Preservation Technology (APT) conference in September, 2018. A more in-depth paper by the same author and colleagues Derek Trelstad and Rebecca Buntrock will appear as an article in the APT Bulletin in 2019.</p>

Pipe Stress and Turbine Nozzle Load Analysis for HP Steam Inlet and MP Steam Extraction on Turbine Generator 51G201T Capacity 10MW

Thermal pipe expansion on the turbine greatly affects the performance of the turbine, mainly produces misalignment in turbines. The stress analysis on the pipe and the load on the nozzle is very important to ensure that the stress that occurs is still safe and the load that occurs on the nozzle is still below the allowable load. Field information is known, Steam type of 51-G-201-T, capacity 10 MW, total weighs 58 tons, weight casing 37 tons, which has been operating since July 1989, has been occur misalignment on turbines. Stress pipe and load analysis of turbine nozzles on the turbine using software (Autopipe V8i Select Series 3 Edition by Bentley). In this perspective, calculation methodologies were developed in order to do quick analysis of the most common configurations, according to the codes ASME B31.1 (Piping Power). The results of the pipe stress analysis showed that the maximum sustained stress ratio occurred at point A39 (0.32), maximum displacement stress ratio at point A39 (0.97) and maximum hoop stress ratio at point A09 (0.44), all values below 1. This shows that the stress is still safe. The result of load analysis on the turbine casing is the direction x = -880 kg, y = 6246.4kg, z = -3697.7kg, smaller than the weight of the 37 tones turbine casing, so misalignment is not caused by shifting the turbine casing.