Målet med detta arbete var att belysa skillnaderna mellan ett fyravåningshus med trä- respektive halvprefabricerad betongstomme ur ett tekniskt perspektiv för att utröna vilket stomalternativ som är att föredra. Faktorer som belystes var: Tjocklekar på bärverksdelar Längsta möjliga spännvidder Installationsmontering Elementmontering Grundstorlek Ljudisolerande förmåga Risk för fuktskador Branddimensionering Projekteringskomplexitet Bygghandlingar från ett befintligt flerbostadshus med trästomme erhölls och analyserades, och ett hus med likvärdig stomme av betong projekterades. Bärverket med halvprefabricerad betong dimensionerades efter rådande Eurokoder och detaljer utformades enligt gällande lagar och regler samt erkänd branschstandard. Ur de tekniska perspektiv som avhandlats i denna rapport väger fördelarna med betong något tyngre än träalternativets fördelar trots att egenskaperna i vissa hänseenden är mycket lika. Betongalternativet ger stora fördelar vad gäller brand och ljud och är samtidigt enklare att projektera, medan trä har sina fördelar i montering och grundläggning. Att välja en stomme av trä till ett flerbostadshus verkar också ha fördelar i de icke avhandlade aspekterna, t.ex. miljö och arbetsmiljö. För att uppfylla ljud-, brand- och fuktkrav i ett trähus krävs det avancerade byggsystem som innebär stor komplexitet i projekteringen vilket kräver ett nära samarbete mellan träprojektör och fabrikör. / The goal with thisdegree project was to highlight the differences between an apartment building with a timber frame and partly prefabricated concrete frame from a technical point of view to determine which alternative that is preferable. Highlighted factors were: Thicknesses of load-bearing parts The maximum length of floor structures Assembly of installations Assembly of the frame-parts Sound-insulating ability Moisture problems Dimension of fire-protection Project-complexity Construction documents from an existing apartment building with a timber frame were obtained and analyzed, and a concrete frame house with similar abilities was projected. The half-prefabricated concrete construction was designed with current eurocodes and details were designed according to laws, regulations and recognized industry standards. From the technical perspective that has been discussed in this report, the advantages with concrete frames are greater than the timber alternative, despite the fact that they in some aspects are very similar. The concrete option provides significant benefits in terms of fire and sound abilities and it is also easier to design, while the timber option has its advantages in assembly and foundation. Choosing a frame of timber to an apartment building also seems to have advantages in the environmental and work environmental aspects. To fulfill the sound, fire and moisture requirements which are needed in a timber house it requires advanced building system that involves complexity of the design which requires close cooperation between the constructional engineer and the manufacturer.

The object of this study was to investigate the recent developments in the use of precast prestressed concrete members for buildings in the United States and Iran. In the United States, the study was concerned with developments in the usage of members such as slabs, wall panels, beams and columns. The latest technical and engineering reports, along with personal interviews, were used, and a number of case studies were conducted on recently built structures. The author also studied the newest developments in the precast concrete industry in Iran. A questionnaire was formulated in both Persian (native language of Iran) and English, and was sent to twelve of the largest precast concrete manufacturers in Iran. This study was extended to include the use of precast concrete members in alleviating Iran's housing shortage, which is one of the greatest problems facing the country today. From these studies the following observations have been made with respect to the United States: There is a vast variety of precast concrete units designed and manufactured in the country. The majority of precast concrete units in buildings are assembled by using simple connections. There has been great improvement in the quality of sealant materials. In the case studies conducted, it was evident that proper planning in design, production, transportation and erection of members were the major reasons in lowering the cost of precast concrete structures as compared to cast-in-place structures. The rapid increase in the use of precast concrete members is due to repetition of similar members, increase in strength and serviceability by prestressing, rapid construction, better quality control, improvement in handling and fire resistance qualities. In the case of Iran, the following observations have been made: The use of precast concrete members has increased rapidly in the last decade. Precast concrete construction, with proper sheer design, appears suitable in areas where there is stronger and more frequent earthquake occurrence. Precast concrete members are considered to be suitable for low-cost housing projects because of the availability of cement and steel reinforcement, an inadequate supply of wood and also because of the advantages of precast concrete mentioned above.

Insulated concrete forms (ICFs) are green building components that are primarily used for residential wall construction. Unlike most polystyrene based ICF variants, the Faswall ICFs used in these experiments were significantly denser because they were made from recycled wood particles and cement. The current design approach for structures constructed with this type of wall form only allows the designer to consider the contribution of the reinforced concrete cores. Previous research has shown that this approach may be conservative. This project experimentally evaluated the lateral structural response of these types of grid ICF walls under increasing amplitude of in-plane cyclic loading. Two different height-to-length (aspect) ratios (approximately 2:1 and 1:1) were investigated, as was the effect of simultaneous gravity load. Furthermore, the reinforced concrete grid was exposed for each aspect ratio in order to examine the contribution of the ICF blocks to the lateral response. Analyses of hysteretic behaviors and failure modes indicated conservatism in the current design approach for estimating lateral strength and ignoring the beneficial contribution of the ICF blocks to overall performance. The presence of the wall forms increased the lateral shear capacity of the walls by an average of 42% (compared to the walls with forms removed), while also increasing the deformation capacity by an average of 102%. Furthermore, by considering an additional gravity load of 10 kips-per-lineal-foot (klf), the shear resistance of the walls increased by 32% (versus walls only subjected to self-weight), on average, and the deformation capacity of the walls increased by an average of 19%. Comparisons of the experimental results to several design equations led to the recommendation of a design equation that was previously accepted for another type of ICF system.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering; and, (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: p. 175-178. / by Joseph Gilmary Burns. / M.S.

Die Umsetzung der Ziele des DFG-Schwerpunktprogramms (SPP) 1542 „Leicht Bauen mit Beton – Grundlagen für das Bauen der Zukunft mit bionischen und mathematischen Entwurfsprinzipien“ erfordert eine Anpassung grundlegender, im Stahlbetonbau etablierter Konstruktionsformen. Ein Beispiel hierfür ist die Stahlbetonskelettbauweise. Aktuelle Konstruktionen weisen klare Strukturen aus Stützen, Unterzügen und Decken, im Regelfall mit rechteckigen, über die Bauteillänge konstanten Querschnitten auf. Um diese typischen Konstruktionen zu optimieren, können die im Rahmen des SPP 1542 an der TU Braunschweig entwickelten Bauteil-, Füge- und Herstellungstechnologien genutzt werden. Um dies exemplarisch zu zeigen, wurde der Demonstrator uni-con² entwickelt und hergestellt. Der Demonstrator stellt einen Ausschnitt eines innovativen Tragwerks aus Hochleistungsbeton dar, das aus Platten- und Stabelementen, die nach dem Prinzip „form follows force“ an die einwirkenden Beanspruchungen angepasst werden, zusammengesetzt wird (Bild 1). Die vorgefertigten Elemente werden trocken gefügt. So kann der Aufbau beschleunigt und eine direkte Belastung ermöglicht werden. Die Verwendung von Trockenfugen erfordert eine hohe Präzision bei der Herstellung der Bauteile. Dies kann durch den Einsatz von hochpräzise hergestellten Schalungen sichergestellt werden. Der symmetrische Aufbau der Tragkonstruktion sowie die gleichbleibenden Spannweiten ermöglichen die multiple Verwendung der komplexen Schalungen. In Kombination mit der Reduktion des Zementverbrauchs ermöglicht dies zudem die Einsparung von natürlichen Ressourcen und Energie. / The implementation of the objectives of the DFG Priority Programme (SPP) 1542 “Concrete light – Future concrete structures using bionic, mathematical and engineering formfinding principles” requires the modification of fundamental structural forms established in reinforced concrete construction. An example of this is the reinforced concrete framework construction. Current constructions show distinct structures consisting of columns, beams and slabs, usually having rectangular cross-sections that are constant over the entire length of the component. In order to optimise these standard structures, the construction, joining and manufacturing technologies developed within the scope of SPP 1542 at Technical University (TU) Braunschweig can be used. The demonstrator uni-con² was developed and manufactured to exemplify this. The demonstrator represents a cutout of an innovative load-bearing structure made of high-performance concrete, which is composed of slab and beam elements designed according to the “form follows force” principle and adapted to the relevant stresses (Fig. 1). The prefabricated elements are joined dry. In this way the assembly can be accelerated and a direct loading can be made possible. The use of dry joints requires high precision in the production of the components. This can be achieved by high precision formwork. The symmetrical configuration of the structure and the constant spans allow the multiple use of the complex formwork. In combination with the reduction of cement consumption, this also enables the saving of natural resources and energy.

A Windows based post processor for the design of reinforced concrete space frames is developed. The post processor is capable of designing beams and columns of reinforced concrete space frames in accordance with the ACI specification. The program is developed in C++ using the object oriented programming approach. The objects used in the program represents a one to one analogy with objects in the real world. The computer model of a structure is composed of objects like members, joints, loads, beams and columns. The development of the post processor is discussed and the program architecture is presented. The design results obtained from the post processor are compared with those obtained from several commercial structural design programs to ensure the correctness of the design. It was concluded that the application of object oriented programming techniques results in programs that are easier to develop and maintain and also greatly reduces the effort required for developing applications for graphical user interfaces. / Master of Science

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Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Pre-cast sections have the advantages of structural efficiency, better quality control and less construction time, which enable them to be widely used in building structures. The connections of pre-cast buildings play a vital role for the stability and strength of structures. Nowadays, more attention is drawn to the aesthetical appearance of building structures, especially by architects. The Hidden Corbel Connection (HCC) was then developed to make the building structures stable and aesthetically pleasing. A modified HCC was designed and investigated in this study. Amongst all the mechanisms in the connection zone, the mechanism of the end anchorage length of tension reinforcement plays a key role in the economy of the connection and is hence further investigated. In order to investigate whether the end anchorage length of tension reinforcement can be reduced for a simply supported beam, a 2D non-linear finite element model is used to analyze the stress distribution inside the connection zone. Based on the stress distribution in the connection zone, the tensile force was calculated at the face of the support, which directly correlates to the required end anchorage length of tension reinforcement. The confinement in the connection zone increases the bond stress, which in turn reduces the required anchorage length of tension reinforcement. Therefore, a 3D model is used to analyze the region inside the modified HCC to find the position of the best confinement. By comparing the finite element (FE) results with Eurocode 2 (2004), and SABS 0100-1 (2000), it is demonstrated that the FE results require the shortest anchorage length, while the longest anchorage length is specified in SABS 0100-1 (2000). Based on the comparison between the FE results and the design codes, a laboratory experiment was then performed to determine if the end anchorage length of tension reinforcement can be reduced. Four beams with different support conditions and with different end anchorage length of tension reinforcement were tested. The results of the laboratory experiment indicate that the end anchorage length for simply supported beams can be shortened from the specification of SABS 0100-1 (2000).

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: This thesis is a study in the use of precast modular construction as an alternative to current methods of school construction in South Africa. Precast Modular Construction is a concept which utilises the principles of prefabrication and precast concrete. Concrete components, be they beams, columns, slabs or full volumetric modules, are manufactured either off-site in factories or in on-site facilities. These components are then assembled on-site to form the structural envelope of a building. This approach contains many inherent advantages: Time is saved due to on-site and off-site work happening concurrently and hence earlier building occupancy results which directly translates to cost reparation; quality is improved due to most of the work being carried out in a controlled factory environment; and health and safety is heightened. However, when viewed from a South African perspective, the fact that less work is done on-site indirectly implicates job loss, a serious issue in the country. Furthermore, implementing a prefabricated approach in the construction of South African schools requires a complete restructuring of the Department of Public Works’ current procurement approach. Prefabrication requires maximum integration between all parties to a project so that design and constructability issues can be addressed at an early stage. The design-build contract strategy is found to be the most integrated approach and allows for optimal collaboration between all project members. However, to only change the procurement route would not suffice as a complete solution. A broader approach is required which addresses issues prevalent in South Africa. These issues include job creation and the establishment of a sustainable and knowledgeable industry. Concepts such as standardisation and strategic partnering, in response, satisfy the need of the manufacturer - for economies of scale, and the employee - for creation of secure working environments. Verification is obtained from all of the aforementioned to propose that the optimal solution to successfully implement Precast Modular Construction for schools in South Africa would be to implement a design-build procurement approach, whereby a single design-build contractor is awarded by the Department of Public Works a contract, via competitive tendering, for the construction of a predetermined number of schools, preferably exceeding 3, over a given contract period using a standardised design and utilising customisable standardised prefabricated precast construction systems, i.e. Precast Modular Construction. This proposal will theoretically result, amongst other things, in the following: - Precast manufacturers will have a confirmed number of orders for products, and can hence be assured of a constant flow of income. This translates directly to an increase in both employment and job security at the manufacturing plant. - The economies of scale principle is satisfied and prefabricated components can therefore be manufactured or ‘mass customised’ in the most feasible way possible. - The design-build contractor will be guaranteed employment for a given period, once again providing job security for its employees, of which the number can also potentially increase. - The design-build contractor carries with it experience and lessons learned from each successfully completed project on to the next, and so becomes more proficient, resulting in better, higher quality schools delivered in shorter periods and with increased efficiency. It is recognised that the proposal is untested in practise but in a socio-economic situation such as South Africa, where large numbers of schools are required quickly, the above proposal makes sense. To additionally develop this hypothesis, further research is required in the fields of design-build procurement and strategic partnering. / AFRIKAANSE OPSOMMING: Hierdie tesis is 'n studie in die gebruik van modulêre voorafvervaardigte beton konstruksie as 'n alternatief vir die huidige metodes van skool konstruksie in Suid-Afrika. Modulêre voorafvervaardigte beton konstruksie bevat baie inherente voordele. Tyd word bespaar as gevolg van werk wat gelyktydig op en van die terrein af gebeur. Dus word die gebou vroeër betrek wat direk lei tot kostebesparings. Kwaliteit verbeter as gevolg van meeste van die werk wat in 'n beheerde fabriek omgewing uitgevoer word en as sulks lei tot beter gesondheid en veiligheid van werkers. Egter, vanuit 'n Suid-Afrikaanse perspektief impliseer die feit dat daar minder werk op die terrein gedoen word indirek werksverlies, 'n ernstige probleem in die land. Die implementering van 'n voorafvervaardigde benadering tot die bou van skole in Suid-Afrika vereis verder 'n volledige herstrukturering van die huidige verskaffing model. Voorafvervaardiging vereis maksimum integrasie tussen alle partye sodat projek ontwerp en boubaarheid op 'n vroeë stadium aangespreek kan word. Die ontwerp-bou kontrak strategie is die mees geïntegreerde benadering en laat toe vir optimale samewerking tussen alle projek lede. Om egter net die verskaffing roete te verander, sou nie voldoen as 'n enkele oplossing nie. 'n Breër benadering word vereis wat kwessies algemeen in Suid-Afrika aanspreek. Hierdie kwessies sluit in werkskepping en die vestiging van 'n volhoubare en kundige industrie. Konsepte soos standaardisering en strategiese vennootskap, as oplossings, voldoen aan die behoeftes van die vervaardiger - vir 'n ekonomieë van skaal, en die werknemer - vir die skepping van 'n versekerde werksomgewing. Die voorafgaande bevestig dat die optimale oplossing vir suksesvolle implementering van Beton Modulêre Konstruksie vir skole in Suid-Afrika sou wees om 'n ontwerp-bou verskaffingsprosedure te volg. Hierdeur kan 'n kontrak aan 'n enkele ontwerp-bou kontrakteur deur die Departement van Openbare Werke toegeken word, deur middel van ‘n mededingende tender proses. Daar word voorgestel dat die projek, vir die konstruksie van 'n voorafbepaalde aantal skole behoort te wees, verkieslik meer as 3, oor 'n bepaalde kontrak tydperk met behulp van 'n gestandaardiseerde ontwerp. Voorts word daar voorgestel om gebruik te maak van aanpasbare gestandaardiseerde voorafvervaardigde beton konstruksie stelsels, dws Beton Modulêre Konstruksie. Hierdie voorstel sal teoreties, onder andere, die volgende gevolge hê: - Beton vervaardigers sal 'n bevestigde aantal bestellings vir produkte hê, en kan dus verseker wees van 'n konstante vloei van inkomste. Dit lei direk tot 'n toename in indiensneming en werksekerheid by die fabriek. - Die ekonomieë van skaal beginsel is bevredig en voorafvervaardigde komponente kan dus vervaardig word in die mees haalbare manier moontlik. - Die ontwerp-bou kontrakteur is gewaarborg van indiensneming vir 'n gegewe tydperk, as sulks ook die verskaffing van werksekerheid vir sy werknemers, waarvan die aantal moontlik ook kan vermeerder. - Die ontwerp-bou kontrakteur neem ondervinding en lesse wat geleer is uit elke suksesvolle voltooide projek saam na die volgende een, en raak dus meer bedrewe, wat lei tot beter, hoër gehalte skole gelewer in korter tydperke en met toenemende doeltreffendheid. Die voorstel is egter ongetoets in die praktyk, maar in 'n sosio-ekonomiese situasie soos die van Suid-Afrika, waar 'n groot aantal skole vinnig benodig word, maak die bogenoemde voorstel sin. Om hierdie hipotese te ontwikkel, is verdere navorsing nodig in die gebied van ontwerp-bou verskaffing en strategiese vennootskappe.