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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Testing of emergency wood shoring towers for use in urban search and rescue operations

McCord, Scott Jacob 25 June 2012 (has links)
Emergency wood shoring towers are utilized by Urban Search & Rescue (US&R) specialists to temporarily stabilize a damaged structure. Standardized designs for wood shoring towers have been developed and are published in manuals for use in US&R operations. These designs have been validated largely through past testing under simplified vertical loading. Research was conducted to provide additional insight into the performance of two common types of shores, the laced post (LP) shore and the plywood laced post (PLP) shore, under non-ideal (other than vertical) loading scenarios. Shores were tested under vertical load only, under lateral load only, and under combined vertical and lateral load. For lateral loading, some shores were tested under monotonic lateral load (lateral load applied in one direction only) and some were tested under cyclic lateral loading. Each specimen was tested to failure, and the documented capacity compared to the FEMA specified shore design capacity. Early warning signs of shore distress known as "fuses" characterized by audible cracking sounds, cupping of the wedges, or cracking of members were also evaluated during testing for their effectiveness and consistency. The performances of the laced post and plywood laced post shores were compared and recommendations made. / text
2

Short-term and long-term behavior of tiebacks anchored in clay

Ludwig, Harald. January 1984 (has links)
No description available.
3

An evaluation of southern ponderosa pine for mining uses

Patchet, Stanley John, 1943- January 1966 (has links)
No description available.
4

Short-term and long-term behavior of tiebacks anchored in clay

Ludwig, Harald. January 1984 (has links)
The development of a more rational design procedure to predict not only ultimate tieback capacities in cohesive soils, but associated tieback displacements as well, requires a basic understanding of short-term and long-term tieback behavior. In view of the above, a series of full-scale and model tieback tests were conducted on instrumented and non-instrumented straight-shafted, postgrouted, and single-underreamed tiebacks anchored in different cohesive soils. In addition, laboratory shear strength tests were conducted on soil-soil samples and grout-soil samples to allow a better interpretation of field and model results. A better understanding of (1) the load-transfer mechanism of each type of tieback and (2) both time-independent and time-dependent component movements has led to the development of a physical model to describe short-term and long-term tieback behavior in a cohesive soil.
5

Establishing a Shared Services Centre in Prague- SAP BSCE Study Case / Establishing a Shared Service Centre in the Czech Republic

Nguyen Ngoc, Huong January 2010 (has links)
The Thesis is conducted based on analysis of a business shared service centre, all factors to consider before the establishment, its scope, model, and the most important is to see advantages as well as to realize the shortcomings of this kind of business model. The country which is analyzed is the Czech Republic; more particular is the city of Prague; and the company is SAP Business Service Centre of Europe (BSCE). In this Thesis, first of all, the PEST (Political, Economic, Social and Technology) environmental analysis has been conducted. The work continues with the SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis of the company SAP AG, from which, we can see that opening a SAP BSCE is a part of SAP strategy which supposes to benefit the company. In order to establish the BSCE, the SAP management board has to consider the factors such as Organization, People, Processes and IT Infrastructure. After analyzing approximately 20 cities in Europe, SAP has chosen Prague as the best mix of quality and costs factors. SAP BSCE covers the functions of Human Resource and Finance and Administration, which provide services to internal and external customers of many countries in Europe, Middle East, and Africa. SAP BSCE has brought back many advantages such as cost-savings, high quality service, business availability and flexibility, and business transparency and legal compliance. On the other hand, there are still many short-comings, such as the high turn-over rate of staff, difficulties in harmonization and standardization of processes and IT infrastructure, and how to prove the quality of service. Despite these challenges, SAP BSCE has put efforts into trying to overcome these problems. At the end of the Thesis, as per analysis of SAP financial results of business activities during the crisis, it is proven the setting up a shared service centre was a good decision of SAP and it paid off with the contribution to help SAP overcome the impacts of crisis.
6

Optimering av stämprivningstider : - En kvantitativ undersökning om stämprivningstider avbostadsbjälklag / Optimization of shoring and reshoringtimes : - Quantitative study to optimize shoring times of residential floors

Öberg Löfstrand, Leonard, Lagerstam, Fredrik January 2018 (has links)
Vid gjutning av bostadsbjälklag är formbyggnad och stämprivning ett viktigt moment. Inombyggbranschen råder vissa tveksamheter angående när och hur stämpen skall rivas. Instruktioner förhur det skall gå till finns att tillgå men de är ofta svårtolkade och i viss mån utdaterade. Det leder tillatt de i många fall inte följs. Hjälpmedel som mätinstrument och simuleringsprogram för detta finnsmen används sparsamt. För att undvika olyckor och säkerställa att betongens hållfasthet är tillräckligutan hjälpmedel används överdrivna tidsmarginaler och detta leder sannolikt till att stämp blirståendes längre än vad som krävs.Under arbetets gång studeras stämp och gjutningsprocessen i detalj för att kunna skapa en tydligbild över hur de ingående faktorerna vid valvgjutningar påverkar varandra. Syftet är att föreslå enlämplig tidpunkt för stämprivning vid valvkonstruktioner. Detta utförs för att kunna avgöra ifall detfinns någon större förbättringspotential, dels när det gäller att motverka slösaktighet av resurser ochförbättra arbetsmiljön men även för att se över instruktionerna för tillvägagångssättet vidformrivning.De metoder som används för att nå resultatet är:● Litteraturstudie av de dokument som beskriver tillvägagångssättet vid stämprivning.● Mätningar med instrument som beräknar hållfasthet vid gjutningar av bostadsbjälklag.● Simuleringar av hållfasthet i programmet Hett 11.● Intervjuer av sakkunniga inom branschen.Resultatet av studien visar på stora skillnader mellan hur länge stämpen står i praktiken och hurlänge de enligt teorin behöver stå. En anledning till detta är att uttorkningstiderna är styrande underproduktionen. Detta medför att högre betongkvaliteter och snabbare härdningstider än de somprojekterades används i byggandet, speciellt vid låga temperaturer. Slutsatsen är att det finnsförbättringspotential inom området. Säkerhetsstämpning kan utföras endast ett par dagar eftergjutning vid goda förhållanden. Fördelarna med detta är att antalet stämp kan minskas, vilket ledertill minskade hyror, samt att framkomligheten för kommande yrkesgrupper och arbetsmoment kanförbättras. / When casting a residential floor, formwork and shore removal is an important element. There aresome doubts in the industry about when and how to remove the shores. There are instructionsavailable but they are often outdated and difficult to interpret. As a result, they are often notfollowed. Appliances such as measuring equipment and simulation software are available but areused sparingly. To avoid accidents and to ensure that the strength of the concrete is sufficientwithout appliances, excessive time margins are used. This will most likely result in unnecessarily longshoring times.During the course of the work, the subject will be studied in detail to create a clear picture of howthe many different factors of the casted floor influence each other. The purpose is to propose asuitable time to remove the shores. This is done in order to determine if there is improvementpotential, partly to improve the working environment, but also to review the instructions of theapproach.The methods used to reach the result are:• Study of the documents describing the procedure of shoring and reshoring• Calculate the compressive strength of the concrete with the device “BI Distant”• Simulate the compressive strength of the concrete in the program Hett 11.• Interviews by experts in the industry.The results show that the shores could theoretically be removed earlier compared to when they areusually removed in practice. One reason for this is that drying times are governing during theproduction. This means that increased concrete qualities and faster curing times than those thatwere planned, were used in construction, particularly at low temperatures. The conclusion is thatthere is an improvement potential in this area. Reshoring can be done only a few days after castingunder good conditions. The advantages of this are that the number of shores can be reduced. Thisleads to reduced rents, and the accessibility for the subsequent professionals and operations can beimproved.
7

Modellering av tidig rivning av bärande form och stämpborttagning

Olsson, Alexander January 2019 (has links)
Bakgrund: En bärande formbyggnad har uppgiften att bära den färska betongen tills bjälklaget uppnått tillräcklig hållfasthet. Kostnaden för formbyggnaden står för en stor andel av den totala kostnaden. En tidigare formrivning ligger därför i entreprenörens intresse att göra projektet mer effektivt och lönsamt. Syftet med den här studien är att studera vilka faktorer som begränsar en tidigare formrivning. Metod: En Revitmodell importerades till Robot Structural Analysis där linjärelastiska analyser har genomförts. Delmodeller skapades beroende på studerad fråga. Produktionsplanering Betong (PPB) användes för att simulera betongens hållfasthetsutveckling. Elasticitetsmodulen beräknades och reducerades med kryptal för att använda det effektiva kryptalet vid analyserna. Dimensioner på stämpen har hämtats från formleverantörens hemsida och laster från Eurocode. Resultat: Studien visar att sprickor uppstår över väggar vid en tidigare formrivning. Resultatet i den här studien visar även att de initiella nedböjningarna samt stämplasterna är obetydliga vid en tidigare formrivning. När stämpning sker mot bottenplattan tar säkerhetsstämpen upp den mesta av lasten. När säkerhetsstämpen avlastas helt från bottenvåningen utsätts betongbjälklagen för högre moment och nedböjning. / Background: A load bearing formwork has the task of carrying the fresh concrete until the floor has reached sufficient strength. The cost of the formwork account for a large proportion of the total cost. Therefore, an earlier removal of the formwork is in the entrepreneur´s interest, to make the project more efficient and profitable. The purpose of this work is to study which factors limit an earlier removal of the formwork. Method: A Revit model was imported into Robot Structural Analysis where linear elastic analyzes have been done. Sub-models were created depending on the question studied. Produktionsplanering Betong (PPB) was used to simulate the concrete´s strength development. The modulus of elasticity was calculated and reduced by the creep coefficient to use the effective modulus of elasticity in the analyzes. Dimensions of the shores have been taken from the supplier´s website and loads from Eurocode. Results: The study shows that cracks occur over walls when removing the formwork earlier. The results of this study also show that the initial deflections and the shoring loads are insignificant at an earlier removal of the formwork. While using reshores against the bottom plate, the reshores takes up most of the loads. When the reshores are fully unloaded from the ground floor, the concrete floor is exposed for higher moment and deflections.
8

Investigação teórica e experimental da transferência de cargas entre pavimentos de concreto escorados / Theoretical and experimental investigation of load transfer between anchored concrete pavements

Salvador, Paulo Fernando January 2013 (has links)
Este trabalho investiga, teórica e experimentalmente, a transferência de cargas que ocorre entre pavimentos de concreto armado ligados por meio de pontaletes, bem como busca identificar eventos e procedimentos que promovam ações críticas de execução. Em recente revisão, as normas da ABNT sugerem uma maior preocupação com as ações aplicadas nas estruturas, com o concreto ainda jovem. A literatura nacional e internacional pesquisada também indica a ocorrência de manifestações patológicas decorrentes de deformações excessivas nas estruturas devida às ações de construção que, inclusive, podem superar o que é previsto em projeto. Neste trabalho é desenvolvida uma metodologia experimental e são mostradas duas análises experimentais em edifícios de andares múltiplos, com ciclos acelerados de execução. Foi instrumentado o escoramento remanescente e o reescoramento de uma parte representativa das estruturas, através da colocação de células de carga, com o objetivo de medir as cargas que são transferidas para os pavimentos por meio dos pontaletes. O primeiro ensaio contou com a instrumentação de dois pontaletes, correspondentes ao escoramento remanescente, em uma laje de tamanho médio, em quatro pavimentos consecutivos. Já o segundo ensaio contou com a instrumentação de oito pontaletes, correspondentes ao reescoramento, em uma laje de grandes dimensões em um único pavimento. Várias situações foram observadas nos experimentos, tais como: sensibilidade frente às variações térmicas, fluência no concreto, aperto descontrolado dos pontaletes em condição de reescoramento, entre outros aspectos importantes. Os resultados mostraram um grande potencial investigativo das técnicas de execução e manuseio dos sistemas de escoramento, escoramento remanescente e reescoramento, inclusive a necessidade de ampliar a investigação experimental. Identificou-se que os modelos teóricos necessitam de uma majoração de valores e que as formas de aplicação das cargas pelos pontaletes nas lajes influenciam, fortemente, a grandeza das solicitações, provocando importantes perdas de segurança. Concluiu-se que há necessidade de se ampliar as combinações de carregamento de projeto, com níveis de carga de acordo com as etapas construtivas e com modo de aplicação compatível com a quantidade e posição dos pontaletes. / This paper investigates, theoretically and experimentally, load transfer that occurs between reinforced concrete pavements connected by props and seeks to identify events and procedures that promote critical actions for implementation. In a recent review, ABNT codes suggest a greater concern on the actions applied to structures with a still young concrete. The national and international literature consulted also indicates the occurrence of pathological manifestations resulting from excessive deformations in structures due to construction actions which may overcome what is expected on the project. An experimental methodology is developed in this work and two experimental analyses on multi-storey buildings with accelerated execution cycles are shown. The shoring remaining and the re-shoring of a representative proportion of the structures were instrumented by placing load cells, intending to measure the loads that are transferred to the pavements through the props. The first test involved the instrumentation of two props, corresponding to the remaining shoring, on a medium sized slab, in four consecutive pavements. The second test involved the instrumentation of eight props, corresponding to the re-shoring, in a large slab on a single deck. Several situations have been observed in the experiments such as sensitivity to thermal variations, creep in concrete, uncontrolled tightening of props on re-shoring condition, among other important aspects. The results showed a great potential investigative of the implementing technical and handling of shoring systems, remaining shoring and re-shoring, including the need to expand the experimental investigation. It was identified that the theoretical models require an increase of values and that forms of application of the loads on the slab by the props, strongly influence the magnitude of requests, resulting in significant loss of security. It was concluded that it is important to expand the loading project combinations with load levels according to the constructive stages and application mode, consistent with the amount and position of the props.
9

Marketing Opportunities for Companies Back-shoring to France

COGNE, Edouard, GUYARD, Arnaud January 2012 (has links)
Purpose of this paper: This paper aims at studying which marketing opportunities companies back-shoring to France can leverage through Mass Media communication. Design/methodology/approach: 2 analyses are performed: a Media analysis studies the message that is sent to consumers. A survey is then carried out to discover how consumers perceive what is broadcast. Hypotheses are designed based on the former, and guide the design of the survey. The discussion and analyses are made under a marketing approach. Findings: The phenomenon is globally understood, but Media are not always necessarily the most appropriate tool for back-shoring companies to communicate about the three marketing dimensions identified during Media analysis: Made-in-France, Social issues related to Sustainable Development and the Impact of Political Messages. Research limitations/implications: The analyses are restricted to a study of French Mass Media, and of French consumers. Therefore, this study cannot be generalized to other countries. What is original/value of paper: This paper helps complete the limited literature on back-shoring, especially in the area of Marketing. This study intends to benefit back-shoring companies willing to develop their marketing strategy.
10

Speeding Up the Process of Modeling Temporary Structures in a Building Information Model Using Predefined Families

Sabahi, Parsa 2010 December 1900 (has links)
It has been less than a decade that Building Information Modeling (BIM) has been used in construction industries. During this short period of time the application of this new modeling approach has increased significantly, but still the main users of such models are architects (for design purposes) and general contractors (for coordination purposes). Most of the BIM applications are developed to meet design and coordination requirements; yet sub-contractors face hassles when using this new technology to model their products, equipment and services in detail. The literature reveals that one of the reasons is they do not have access to the tools and objects they need to model their work within the BIM environment. Temporary structures, such as shoring systems and formworks, are good examples. Although these structures play a significant role in the logistics of the jobsite, there are neither a special tools nor predefined objects in BIM applications to help model these elements. In this case study a real building project has been used to model these temporary structures by two different methods: 1. Using ordinary tools in BIM application (Revit), and, 2. Using predefined parametric families of objects developed and customized for this project. During the modeling process, time has been recorded as well as other observations describing obstacles, advantages, and disadvantages of both methods. The results show that the usage of predefined parametric families speeds up the process of modeling and also helps to create a model which is more understandable and informative than 2D drawings that are currently being used by most of the sub contractors.

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