Stage 1 Geotechnical Studies for Interstate 15 Reconstruction Project, Salt Lake County, Utah

Interstate 15 Reconstruction Project includes rebuilding of 137 bridges; widening the existing three general purpose lane roadway to four general purpose lane with a HOV lane and an auxiliary lane roadway, and other associated work such as converting the existing diamond interchanges to single point urban interchanges (SPUI). The project will be built under a design-build procurement process and is anticipated to be completed in 4 ½ years by October of 2001. The subsurface soils beneath the corridor consist of lake deposits (Lake Bonneville), namely soft to medium stiff plastic clays, silts and loose to medium dense sands ranging in thickness over 150 meters. The shallow water table is generally 5 to 10 feet below natural grade. The soft clays have low shear strengths and are highly compressible under embankment loads. The Salt Lake segment of the Wasatch fault is approximately 3.5 kilometer to the cast of the highway corridor. The structures will have to be designed to meet the seismic criteria and take into account the high liquefaction potential of some of the saturated sand lenses. Stage 1 efforts included identification of the various subsurface conditions; evaluation of soil parameters; establishing guidelines for field investigations, laboratory testing; analysis; reporting etc. In addition, various project specific studies were carried out for the proposed reconstruction project, details of which are presented in the paper

as the methods for assessment of health risks

Aim of the work was to investigate the pollutants level specially Nitrate- N in the groundwater and compare the obtained results with WHO standard. Groundwater sample were collected from sixty wells consists of thirty cancer patients well as case and other thirty as control within 100 m distance from highly affected three areas of oesophagus and stomach cancer. Questionnaire was used for case- control study. The determined values expressed by hazard quotient indicate that the water pollutants and their concentrations do not exceed unity. Chunnakam was shown the high odds ratio which was greater than one. But in relative risk was greater than one in all the selected three areas. Ingestion with water is the main pathway for nitrates than the vegetables in areas where groundwater with high nitrate content

An evaluation of functional outcome following minimally invasive plate osteosynthesis in fractures of the distal tibia

Background: Management of fractures of the distal tibia remains a challenging proposition due to the fact that the major part of the bone is in a subcutaneous location and the blood supply is quite precarious. Conventional forms of osteosynthesis are associated with high rates of infection and nonunion. Due to extensive soft tissue stripping, the vascularity is compromised and often results in poor wound healing and tends to compromise fracture healing as well. Closed reduction with minimally invasive plate osteosynthesis (MIPO) addresses these issues and has emerged as a viable treatment option with minimal complications. The aim of this study was to assess the functional outcome MIPO using locking compression plates (LCP).Methods: 32 patients with distal tibial fractures treated by MIPO technique with LCP fixation were studied from January 2012 to January 2014 and were followed up for a period of 2 years.Results: All the fractures in our series united well at the end of 6 months with mean time to radiological evidence of callus formation at 10 weeks and the mean time to fracture union was 20 weeks. There were 2 cases with varus angulation in our series and no cases with implant failure. There were 3 patients with superficial skin infections and no cases of deep infection.Conclusions: We conclude that MIPO with LCP is an effective treatment option for distal tibial fractures avoiding all the complications associated with other forms of internal fixation. We strongly recommend its usage in these types of complex injuries

Radial nerve neurotmesis in closed humeral shaft fracture: unusual case

Radial nerve neurotmesis constitutes a major problem in the treatment of closed fractures of the mid-shaft of the humerus. A case of radial nerve neurotmesis associated with a closed fracture of mid-shaft of the humerus is reported. Radial nerve neurotmesis was found at the fractured site. Early exploration of the nerve and primary internal fixation of the fracture was done which gave a satisfactory result

Fire resistance of bearing walls in light steel frame (LSF) structures including various insulation filler materials by finite element method

Using prefabricated structure in lightweight construction is the new method in both industry and civil engineering. Lightweight Steel Frame (LSF) becomes more valuable in the construction industry due to low cost, low weight, high speed of installation and resistance to environmental conditions. Cold-rolled form lightweight load-bearing wall is consisting of a thin sheet of steel with C-shaped sections (STUD), thermal insulation filler and cover sheets (Plaster Board). However, regardless of existing plasterboard protection the thin-walled steel sections heat up quickly and lose their strength under fire conditions. The main goal of the current study is an evaluation of thermal capacity and bearing strength of lightweight walls in terms of cellulosic fire condition analytically. The variable parameters are insulation filler materials (polystyrene, polystyrene concrete) and axial load. The Abaqus finite element software was used for modeling and analyzing of fire loads. Lightweight concrete fillers increase the axial bearing capacity of walls sustainably and polystyrene filler improved the fire resistance of walls

Finite Element Analyses of Cold‐formed Stainless Steel Beams Subject to Shear

Stainless steel is a high‐performance construction material that combines the strength and stiffness associated with ferrous alloys with the corrosion resistance derived principally from the high chromium content. Its unique combination of properties usually comes at a cost, which puts increased emphasis on ensuring that the material is utilized to the upmost in structural applications. Consequently, in the recent years, an increase in the use of stainless steel in the construction industry has been witnessed, more specifically in exposed architectural applications and where total life economics, durability, improved resistance to aggressive environment, etc. are prime deciding criteria. However, the shear behaviour and capacity of cold‐formed stainless steel beams has not been investigated adequately in the past. Hence, detailed finite element analyses (FEA) were undertaken to investigate the shear behaviour and strength of stainless steel lipped channel beams (LCBs). The developed finite element models were first validated using the shear test results. They were then used in a detailed parametric study to investigate the effects of various influential parameters such as section thickness, depth and grade. Moreover, a parametric study was conducted to emphasize the beneficial effect of strain hardening of stainless steel on shear capacity of LCBs, in particularly for compact sections. FEA results showed that currently available design equations (EN1993‐1‐4) are inadequate to capture the available inelastic reserve capacity of compact stainless steel LCBs, thus suitable equations were proposed to enhance the predictions. This paper presents the details of finite element modelling and analyses of stainless steel LCBs and the development of these new shear design rules

Bending-shear interaction of cold-formed stainless steel lipped channel sections

The bending-shear interaction response of cold-formed stainless steel lipped channel sections has been given inadequate attention in the past. Therefore, this paper investigates the bending and shear interaction behaviour of cold-formed stainless steel lipped channel sections using numerical studies. Finite element (FE) models were developed and validated against the experimental results found in the literature for three-point and four-point loading tests of lipped channel sections of both cold-formed stainless steel and cold-formed steel. The elaborated FE results were used for a comprehensive parametric study that was conducted comprising 60 FE models of three-point loading simulations of stainless steel lipped channels with five different aspect ratios to study the shear response and the bending-shear interaction response. Another 12 FE models of four-point bending simulations were developed to study the bending response. The numerical results were analysed and it is found that the sections with aspect ratios of 1.5 and 2.0 are subjected to the interaction of bending and shear while there is no interaction effect observed in the sections with other aspect ratios. Eurocode 3 and American specifications interaction equations were then evaluated using the numerical results. These design provisions are found to be too conservative for a higher level of applied shear force. Therefore, revised design equations for bending and shear interaction were proposed aiming better prediction accuracy. Further, a statistical evaluation was conducted for the proposed interaction equations and results suggest improved and consistent predictions

Optimised cold-formed steel beams in modular building applications

Modular Building Systems (MBS) has seen an accelerating growth in the construction sector owing to its potential advantages, such as quick erection, improved energy efficiency and less reliant on good weather over conventional construction methods. Therefore, it could be a viable solution to supporting the efforts of solving Britain's housing crisis within a short duration. Construction industries and researchers are working towards better understanding MBS performance at different scales and contexts. To date, research on MBS focused on investigating the structural, social and economic, and safety performances and indicated that there are challenges (Need of lightweight materials and more access space, transportation restrictions, improving structural, fire and energy performances) associated with their use, yet to be addressed. This paper highlights how the incorporation of optimised Cold-Formed Steel (CFS) members with the slotted web can address these challenges. Hence, optimisation technique was employed to enhance the structural performance and to effectively use the given amount of material of CFS members. Lipped channel, folded-flange, and super-sigma have been optimised using the Particle Swarm Optimisation (PSO) method and were analysed using FEM. Results showed that the flexural capacity of the optimised sections was improved by 30–65% compared to conventional CFS sections. A conceptual design of MBS was developed using the optimised CFS members, demonstrating the potential for lighter modules and thus more sustainable structures, reducing the carbon footprint. Therefore, optimisation techniques and slotted perforations would address the aforementioned challenges related to MBS, result in more economical and efficient MBS for inhabitants and construction industries

Structural behaviour of optimized cold-formed steel beams

Cold-formed steel (CFS) members have been used significantly in light-gauge steel buildings due to their inherent advantages. Optimizing these CFS members in order to gain enhanced loadbearing capacities will result in economical and efficient building solutions. This research presents the investigation and results of the optimization of CFS members for flexural capacity. The optimization procedure was performed using the particle swarm optimization (PSO) method, while the section moment capacity was determined based on the effective width method adopted in EN 1993-1-3 (EC3). Theoretical and manufacturing constraints were incorporated while optimizing the CFS cross-sections. In total, four CFS sections – lipped channel beam (LCB), optimized LCB, folded-flange and super-sigma – were considered in the optimization process, including new sections. The section moment capacities of these sections were also obtained through non-linear finite element (FE) analysis and compared with the EC3-based, optimized section moment capacities. The results show that, compared with a commercially available LCB with the same amount of material, the new CFS sections possess the highest section moment capacity enhancements (up to 65 %). In addition, the performance of these CFS sections when subjected to shear and web-crippling actions was also investigated using non-linear FE analysis

Numerical investigation of cold-formed stainless steel lipped channels with longitudinal stiffeners subjected to shear

The shear response of the cold-formed stainless steel lipped channel sections with longitudinal stiffeners has not been investigated adequately in the past. Therefore, this paper presents the details of numerical investigations conducted to study the shear behaviour of longitudinally stiffened cold-formed stainless steel lipped channel sections. Following a validation study of the finite element models of lipped channel sections, the effect of return lips and web stiffeners on the shear response of lipped channel sections was examined through comprehensive numerical parametric studies. In addition, numerical investigations were conducted to study the elastic shear buckling response of the sections and the shear buckling coefficients were back-calculated. It was found that the longitudinal web stiffeners enhance the shear buckling resistance of lipped channel sections considerably with increased stiffener depth. However, the shear capacity increment is not significant compared to plain lipped channel sections. The presence of the web stiffeners is found to be not preventing the out-of-plane buckling of the sections. The evaluation of Eurocode 3 and the direct strength method shear provisions for stainless steel channel sections with longitudinal stiffeners illustrates inaccurate capacity predictions. Therefore, modifications were proposed and comparisons reveal that the proposed provisions enhance the shear resistance predictions with good accuracy over the codified provisions