The aim of this research is to develop a coupled thermo-mechanical damage model for implementation in finite element software in support of fire-induced collapse assessment of steel structures. The need for properly modelling steel deterioration behaviour remains a challenging task in structural fire engineering because of the complexity inherent in the damage states of steel at large strains and high temperatures. A fully three-dimensional damage-coupled constitutive model is developed based on the hypothesis of effective space elastoplasticity and isotropic damage theory. The coupled damage is simulated by a coupling formulation between a mechanical damage component and a thermal damage component in attempt to capture the coupled damage growth under combined actions of mechanical loading and fire loading. The proposed damage model comprises a limited number of parameters that could be identified at unloading slopes of stress-strain relationships through tensile coupon tests. Alternatively, an inverse analysis type of calibration procedure could be adopted when coupon test data is unavailable. The proposed damage model is successfully implemented in the finite element software ABAQUS and calibrated with a comprehensive range of experimental results and established numerical results. The damage-affected structural response is accurately reproduced under various loading conditions and a wide temperature range, demonstrating that the proposed damage model is a useful tool in giving a realistic representation of steel deterioration behaviour under combined actions of fire and mechanical loads. Three-dimensional FE models of a five-storey and a ten-storey steel-framed office building are developed in ABAQUS and the proposed damage model is adopted in assessing their susceptibility to progressive collapse. Three types of accidental scenarios are investigated : (i) fire only scenario, (ii) post-blast fire scenario, and (iii) fire-triggered explosion scenario. The location of the compartment where triggering loads occur is varied and the most vulnerable location is at the mid-height of both building systems. Estimation of ultimate failure time by incorporating damage model with the suggested damage parameter set has the potential to be utilized as a useful tool in helping designers to determine how much time is realistically available for evacuation before progressive collapse occurs in this type of buildings. Results show that the proposed damage model significantly affects the limit state of steel buildings under fire, and especially under combined actions of blast and fire. Compared to conventional numerical approaches, the consideration of coupled thermo-mechanical damage accumulation results in an 8.25% ∼ 23.47% decrease of collapse resisting time. A key finding from this study is that the alternative load path, which is a crucial factor in deciding the survival of buildings upon local column failure, may be severely compromised due to the coupled thermo-mechanical damage propagation in surrounding columns. Based on the identified collapse mechanisms, effective strategies are suggested to improve the survivability of buildings under blast and fire.

Thesis (M.S.) Massachusetts Institute of Technology. Dept. of Building Engineering and Construction, 1956. / Bibliography: leaf [62]. / by George C. Tso. / M.S.

Thesis (M.S.) Massachusetts Institute of Technology. Dept. of Building Engineering and Construction, 1956. / Bibliography: leaf [51]. / by Isaac Tiles. / M.S.

Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1964. / MIT Institute Archives copy bound with three title pages at the beginning of text block; MIT Rotch Library copy has title pages bound with appropriate theses. -- Rotch Library copy missing 16 leaves of plates. / Title from half-title page. Three individual thesis titles bound together with a collective title and an introduction. Compiled, with an introduction, by Prof. Eduardo F. Catalano. / Includes bibliographical references. / Preface: "The three individual theses are presented with a common introductory discussion on systems in general, the use of systems in architecture, and the overall goals and requirements for a building system. It is hoped that a better understanding of systems is attained as well as a more extensive background for the individual thesis material." / Hershdorfer, Selma Abigadol. The development of a building unit which is structurally and mechanically integrated and which allows maximum flexibility in internal rearrangement and lateral growth. (1964) -- Hook, Charles Burton. A research and development building for science and technology suitable for both academic and non-academic use. (1964) -- Hoover, George Norman. An academic/research and development building for science and technology. (1964). / M.Arch.

Supplemental passive dampers are generally considered as an effective tool to control the seismic response of multi-storey buildings. Since the optimum placement of passive dampers in buildings can potentially improve the structural performance or reduce construction cost, there is an increasing number of researchers engaged to optimize the damper placement in buildings. Given that a large number of studies have been conducted to investigate damper placement methods, a systematic method or a clear conclusion for strategically distributing dampers in buildings is not presented in any building guidelines. The main limitations of current damper placement studies may include the lack of focus on collapse resistance of retrofitted buildings, on beam and column nonlinear behaviors, and the lack of considering the variations of earthquake characteristics and intensity levels. The fundamental damper placement issue can be separated as the distribution of dampers throughout the height of the buildings and the distribution of dampers in different bays in building frames. In this research, both distributions are explored and their effect on the collapse performances of buildings under strong earthquakes is thoroughly studied. The effectiveness of advanced damper placement approaches is evaluated by comparisons with classical damper placement methods. Considering the uncertainty in earthquake ground motion characteristics, multiple ground motions scaled to various intensity levels are involved to evaluate the seismic performance of buildings. Finally, major conclusions towards the philosophy of the strategic damper placement in practical building constructions are presented in terms of the overall structural performance under strong ground motions.

Reinforcement corrosion is one of the major causes of deterioration of reinforced concrete structures exposed to aggressive environments. Deterioration caused by reinforcement corrosion reduces the serviceability and load bearing capacity of the concrete structures to an extent of serious structural failure. Consequently, this increases the resources required for the maintenance and rehabilitation over time. Due to uncertainties associated with the performance deterioration, it is difficult to accurately assess the residual strength and remaining useful life of corrosion damaged concrete structure. Therefore, the reliability-based performance assessment techniques based on stochastic deterioration modelling has significant potential for assessing the present and future performance of these structures. This can be ultimately helpful in sustainable and cost-effective infrastructure management. This research presents new analytical methods for evaluating concrete crack evolution, estimating rebar bond strength degradation and predicting residual flexural strength of concrete structures affected by reinforcement corrosion. At first, cracking in cover concrete due to reinforcement corrosion is investigated by using rebar-concrete model and realistic concrete properties. The bond strength evolution of the corroded rebar is then evaluated at different stages of cover cracking by considering adhesion, confinement and corrosion pressure acting at the bond interface. Furthermore, the residual flexural strength of concrete beams is predicted with consideration of bond failure between the rebar and concrete. The gamma process is adopted for stochastic modelling of concrete crack growth and strength deterioration with uncertainties. Then, a time-dependent reliability analysis is undertaken to evaluate the probability of failure in serviceability and load carrying capacity of corrosion damaged concrete beams. Optimal repair planning during the service life is also determined by balancing the cost for maintenance and the risk of structural failure. Finally, the results evaluated from the proposed methods are examined by available experimental and field data and the applicability is demonstrated by numerical examples. The results obtained show that the proposed methods are capable of evaluating the performance and can also provide risk-cost balanced repair strategy during the lifetime of corrosion damaged concrete structures. The knowledge gained from this research contributes to the better understanding of the mechanics of performance deterioration associated with reinforcement corrosion. Furthermore, the methods presented in this study could be helpful in assessing the actual state of performance deterioration and making decision regarding the optimal repair.

Refurbishments have different features in comparison with new build projects. This refers mainly to the fact that they are carried out in an existing asset that might remain in operation. Such characteristics increase the complexity inherent to construction settings. Yet, studies indicate that mainstream practices, that are not capable of dealing with complex projects, are predominantly used for managing production. Prior research suggests that the use of such an incompatible management approach is likely to lead to poor performance. Indeed, problems in managing refurbishments have been identified in several countries. Despite this troubling scenario, the management of refurbishment works has not been properly addressed in the current research agenda. There are numerous studies related to the broad refurbishment area, but only a small number refer to the way those projects are managed. Moreover, the majority of studies about this topic have not been based on a proper theory of production. Clearly, there is a gap in this research domain. In order to fill such a gap, this research aims to developing a method for construction management in refurbishment projects, with the purpose of improving production performance, by indicating appropriate approaches of production control. The method comprises a conceptual model of refurbishments, a framework for project characterisation, and a list of managerial solutions, grounded on a robust theory of production and suited to the context of refurbishments. The constructive research approach is adopted in the study. Two rounds of empirical studies were conducted throughout the research. Firstly, two studies were carried out to obtain a deeper understanding of the topic investigated and to develop the initial version of the method. Secondly, a study was conducted to implement and refine the artefact. Thirdly, a focus group was organised to evaluate the utility of the method, to refine it, and to examine its scope of applicability. The main theoretical contributions of the study, embrace the conceptual model of refurbishments to support effective construction management, the framework having project dimensions for helping managers to cope with the management of complexity innate to refurbishments, and the framework of managerial solutions for production management. In practical terms, the study showed that the application of the method assisted managers in choosing suitable practices for managing construction in a retrofit project and contributed to enhance project performance. Moreover, it is contended that the method can be used to help organisations to get started on lean in refurbishment projects.

Every company strives for maximum efficiency. The construction industry, which is complex while margins are small, makes efficiency an important issue. In the construction industry today,the high demand for production is to be delivering high quality projects as well as within certain timeframes. In order for this to be achieved, there is a great demand for work management in production. Therefore, we have chosen to analyze improvement areas within the supervisor’s role.The purpose of this report is to investigate the supervisor’s situation in the construction industry.Furthermore, the purpose is to identify work-related tasks in the professional role that have the potential for efficiency enhancement.A frequency study has been conducted in three different workplaces where we have followed three different supervisors for a total of nine days to get an insight into how the supervisors spend theirtime. Interviews have been conducted with supervisors for an even broader view of the study. Literature search has been made where we have found theories that we also present. During the course of the study we have found that there are a few improvement areas. As an enhancement, we think digitalization should be implemented, and everyone should keep order and clean up afterwards, more feedback to employees, and develop communication.

Due to the continued advancing of the building industry and the growing number of housing shortages, building on floating components has become an alternative to that on solid land or coastal areas that are geotechnically unsuitable for filling. This can even be done using portable and movable homes. The work is written for Aquashell and the study will describe the possibility of establishing homes on the water surface in Luleå using given floating components. By using suitable building materials and energy supply methods, the building is adapted to Luleå’s sub-arctic climate.   The aim of the work is to design flexible housing which is portable and movable that enables settling on the water surface in colder climates in northern latitudes by the use of suitable materials and building modules.   Firstly, a literature study was conducted on the subject together with studies in the form of interviews and location visits. Then a program was created with requirements for the building. After that a design proposal was made containing appropriate material choices which were then chosen to be visualized in Luleå’s Norra Hamn as a possible residential area.   The floating homes are adapted to the climate and designed with respect to the surrounding environment in order to optimally take advantage of the scenic views in the area.   The hope of the work is to demonstrate the possibility for housing on water by use of floating buildings even in sub-arctic climates. The work can also provide a potential solution in response to the ever-increasing shortage of housing.

Syftet med detta examensarbete är att undersöka om man kan bygga miljömässigt hållbart utan att det behöver kosta mer. På grund av kostnadsökningar för byggandet av miljövänliga hus byggs inte dessa i samma utsträckning som önskat, vilket är nödvändigt då byggsektorn bidrar till stora utsläpp av miljöfarliga ämnen. Vi har undersökt om man kan effektivisera användningen av miljömässigt hållbara material utifrån Sweden Green Building Council’s miljöklassificering från ett kostnadsperspektiv. Av de 15 punkter som presenteras som bedömningskriterier för certifiering Miljöbyggnad av nyproduktioner tittar vi närmare på 3 av punkterna: Energianvändning, ljud och ventilation. Studien har genomförts på uppdrag av Riksbyggen och rapporten riktar sig främst till beställare och entreprenörer men resultatet är något som rör alla som befinner sig i byggbranschen. Informationen som legat till grund för denna rapport är insamlat från tidigare forskning via LiU’slitteratursökningssida samt intervjuer med projektörer, leverantörer och installationssakkunnigför närmare information angående uppdaterade priser och installationsalternativ. I slutsatsen av rapporten kan man se vilka olika byggdelar som har använts vid energiåtgång, ljud och ventilation och vad de olika byggdelarna har kostat, resultatet presenteras som en procentsats i ökning som utgår från BBR’s byggkrav. Även en procentsatssökning har tagits fram på de olika byggdelarna som uppnår nivå silver där mer kostnadseffektiva alternativ presenteras.