Durch computergestützte Methoden zur Formfindung und Strukturoptimierung können heute Betonstrukturen entwickelt werden, die optimal an ihre jeweilige statische Aufgabe angepasst sind. Mit dem reduzierten Material- und Energieverbrauch der optimierten Struktur geht jedoch zumeist eine Geometrie einher, deren Herstellung material- und arbeitsintensiver Schalungstechniken bedarf. Auch vor dem Hintergrund einer absehbaren Knappheit von für die Bauindustrie wichtigen Materialien hat Werner Sobek schon 1999 mit der Triple-Zero®-Maxime – zero fossil based energy, zero waste, zero emission – gefordert, in Bauprozessen idealerweise nur recycelbare Materialien zu verwenden [1]. Dem steht die Forderung gegenüber, dass eine Schalungstechnik die Formgebung, Konstruktion oder Herstellung von optimierten, insbesondere geometrisch komplexen Bauteilen in keiner Weise einschränken sollte. [Aus: Einführung] / Today, computer-aided methods for form-finding and structural optimization can be used to develop concrete structures that are optimally adapted to their structural requirements. However, the reduced material and energy consumption of the optimized concrete structure usually goes hand in hand with complex geometry whose production usually requires material- and labour-intensive formwork techniques. With a foreseeable scarcity of essential construction materials in mind, Werner Sobek back in 1999 coined the Triple-Zero® concept – zero fossil-based energy, zero emission, zero waste – which demands that only recyclable materials should be used in construction processes [1]. Thus, there is a demand for waste-free formwork technology that simultaneously should in no way restrict the shaping, design or manufacture of optimised, and therefore, geometrically complex components. [Off: Introduction]

The first part of the thesis addresses the fatigue performance of concrete bridge decks with GFRP stay-in-place structural forms replacing the bottom layer of rebar. The forms were either flat plate with T-up ribs joined using lap splices, or corrugated forms joined through pin-and-eye connections. The decks were supported by simulated Type III precast AASHTO girders spaced at 1775mm (6ft.). Two surface preparations were examined for each GFRP form, either using adhesive coating that bonds to freshly cast concrete, or simply cleaning the surface before casting. For the bonded deck with flat-ribbed forms, adhesive bond and mechanical fasteners were used at the lap splice, whereas the lap splice of the unbonded deck had no adhesive or fasteners. All the decks survived 3M cycles at 123kN service load of CL625 CHBDC design truck. The bonded flat-ribbed-form deck survived an additional 2M cycles at a higher load simulating a larger girder spacing of 8ft. Stiffness degradations were 9-33% with more reduction in the unbonded specimens. Nonetheless, live load deflections of all specimens remained below span/1600. The residual ultimate strengths after fatigue were reduced by 5% and 27% for the flat-ribbed and corrugated forms, respectively, but remained 7 and 3 times higher than service load. The second part of the thesis investigates the performance of bridge deck overhangs reinforced by GFRP rebar. Overhangs of full composite slab-on-girder bridge decks at 1:2.75 scale were tested monotonically under an AASHTO tire pad. Five tests were conducted on overhangs of two lengths: 260mm and 516mm, representing scaled overhangs of 6ft. and 8ft. girder spacing, respectively. The 260mm overhang was completely reinforced with GFRP rebar while the 516mm overhang consisted of a GFRP-reinforced section and a steel-reinforced section. The peak loads were approximately 2 to 3 times the established equivalent service load of 24.3kN, even though the overhangs were not designed for flexure according to the CHBDC but rather with lighter minimum reinforcement in anticipation of shear failure. The failure mode Abstract ii of each overhang section was punching shear. The steel-reinforced overhang section exhibited a greater peak load capacity (13.5%) and greater deformability (35%) when compared to the GFRP-reinforced overhang section. / Thesis (Master, Civil Engineering) -- Queen's University, 2013-09-17 18:54:18.131

The concept of stay-in-place (SIP) structural formwork has the potential to simplify and accelerate the construction process to a great extent. Fibre-reinforced polymer (FRP) SIP structural formwork offers further potential benefits over existing formwork systems in terms of ease and speed of construction, improved site safety and reduced long-term maintenance in corrosive environments. However, it is not without its limitations, including primarily the possibility of a lack of ductility, which is a key concern regarding the use of FRP structural formwork in practice. This thesis presents the findings of an experimental and analytical investigation into a novel FRP SIP structural formwork system for a concrete slab with a particular emphasis on its ability to achieve a ductile behaviour. The proposed composite system consists of a moulded glass fibre-reinforced polymer (GFRP) grating adhesively bonded to square pultruded GFRP box sections. The grating is subsequently filled with concrete to form a concrete-FRP composite floor slab. Holes cut into the top flange of the box sections allow concrete studs to form at the grating/box-section interface. During casting, GFRP dowels are inserted into the holes to further mechanically connect the grating and box sections. An initial experimental investigation into using GFRP grating as confinement for concrete showed that a significant increase in ultimate strength and strain capacity could be achieved compared to unconfined concrete. This enhanced strain capacity in compression allows greater use of the FRP capacity in tension when used in a floor slab system. Further experimental investigation into developing ductility at the grating/box-section interface showed that the proposed shear connection exhibited elastic-‘plastic’ behaviour. This indicated the feasibility of achieving ductility through progressive and controlled longitudinal shear failure. Following these component tests on the concrete-filled grating and the shear connectors, a total of six (300 x 150 x 3000) mm slab specimens were designed and tested under five-point bending. It was found that the behaviour of all specimens was ductile in nature, demonstrating that the proposed progressive longitudinal shear failure was effective. A three-stage analytical model was developed to predict the load at which the onset of longitudinal shear failure occurred, the stiffness achieved during the post elastic behaviour and, finally, the deflection at which ultimate failure occurred. Close agreement was found between experimental results and the theory.

This study presents a conceptual design process for one-way reinforced concrete slabs cast over Textile Reinforced Concrete (TRC) Stay-in-Place (SiP) formwork elements, aiming at the minimization of the composite slab cost satisfying Ultimate Limit State (ULS) and Serviceability Limit State (SLS) design criteria. The thin-walled TRC element is considered to participate in the structural behaviour of the composite slab. This distinct function of the TRC element (as formwork and as a part of a composite element) distinguishes the design procedure into two States: a Temporary and a Permanent one. Design parameters such as the type of the textile reinforcement (material), the geometry of the TRC cross-section, the flexural strength of the fine-grained concrete in the TRC element and the compressive strength of the cast in-situ concrete are considered as the main optimization variables.

Commercially available glass fiber-reinforced polymer (GFRP) off-the-shelf structural shapes have great potential as stay-in-place open structural forms for concrete structures, including bridge decks and girders. The system simplifies and accelerates construction, and the non-corrosive GFRP forms can fully or partially replace steel rebar. In this study, eight concrete slabs were constructed using flat pultruded GFRP plates, and nine girders were constructed using trapezoidal pultruded GFRP sheet pile sections as stay-in-place structural forms. No tension steel reinforcement was used. All specimens were tested in four-point monotonic uniaxial bending. Four adhesive and mechanical bond mechanisms were explored to accomplish composite action. The most effective mechanism, considering structural performance and ease of fabrication, was wet adhesive bonding of fresh concrete to GFRP. Although failure was by debonding, no slip was observed prior to failure. Other parameters studied were concrete slabs’ thicknesses and their shear span-to-depth ratios. For the girders, three different cross-sectional configurations were examined, namely, totally filled sheet piles, one with a voided concrete fill, and an all-GFRP box girder developed by bonding flat GFRP sheets to the upper flanges of the sheet piles with a cast-in-place concrete flange. Girders were tested in positive and negative bending to simulate continuity. The built-up box girders showed superior performance, with up to 70% higher strength and 65% lower weight than the totally filled sections. It was found that similar size conventional steel-reinforced concrete sections of comparable stiffness have considerably lower strength, while those of comparable strength have considerably higher stiffness than FRP-concrete members. An analytical model was developed to predict the behaviour and failure loads of slabs and girders, using cracked section analysis. A unique feature of the model is a multi-stepped failure criteria check that can detect flexural, shear, or bond failure. The model was successfully validated using the experimental results, and used in a parametric study. It was shown that using the typical value of 1MPa for shear strength of cement mortar predicts debonding failure, which occurs slightly above the interface, quite well. Also, in practical applications of longer spans, flexural failure is likely to occur prior to bond failure. / Thesis (Master, Civil Engineering) -- Queen's University, 2008-07-14 15:12:48.405

Performance of bridges during previous earthquakes has demonstrated that many structural failures could be attributed to seismic deficiencies in bridge columns. Lack of transverse reinforcement and inadequate splicing of longitudinal reinforcement in potential plastic hinge regions of columns constitute primary reasons for their poor performance. A number of column retrofit techniques have been developed and tested in the past. These techniques include steel jacketing, reinforced concrete jacketing and use of transverse prestressing (RetroBelt) for concrete confinement, shear strengthening and splice clamping. A new retrofit technique, involving fibre reinforced polymer (FRP) jacketing has emerged as a convenient and structurally sound alternative with improved durability. The new technique, although received acceptance in the construction industry, needs to be fully developed as a viable seismic retrofit methodology, supported by reliable design and construction procedures. The successful application of externally applied FRP jackets to existing columns, coupled with deteriorating bridge infrastructure, raised the possibility of using FRP reinforcement for new construction. Stay-in-place formwork, in the form of FRP tubes are being researched for its feasibility. The FRP stay-in-place tubes offer ease in construction, convenient formwork, and when left in place, the protection of concrete against environmental effects, including the protection of steel reinforcement against corrosion, while also serving as column transverse reinforcement. Combined experimental and analytical research was conducted in the current project to i) improve the performance of FRP column jacketing for existing bridge columns, and ii) to develop FRP stay-in-place formwork for new bridge columns. The experimental phase consisted of design, construction and testing of 7 full-scale reinforced concrete bridge columns under simulated seismic loading. The columns represented both existing seismically deficient bridge columns, and new columns in stay-in-place formwork. The existing columns were deficient in either shear, or flexure, where the flexural deficiencies stemmed from lack of concrete confinement and/or use of inadequately spliced longitudinal reinforcement. The test parameters included cross-sectional shape (circular or square), reinforcement splicing, column shear span for flexure and shear-dominant behaviour, FRP jacket thickness, as well as use of FRP tubes as stay-in-place formwork, with or without internally embedded FRP crossties. The columns were subjected to a constant axial compression and incrementally increasing inelastic deformation reversals. The results, presented and discussed in this thesis, indicate that the FRP retrofit methodology provides significant confinement to circular and square columns, improving column ductility substantially. The FRP jack also improved diagonal tension capacity of columns, changing brittle shear-dominant column behavior to ductile flexure dominant response. The jackets, when the transverse strains are controlled, are able to improve performance of inadequately spliced circular columns, while remain somewhat ineffective in improving the performance of spliced square columns. FRP stay-in-place formwork provides excellent ductility to circular and square columns in new concrete columns, offering tremendous potential for use in practice. The analytical phase of the project demonstrates that the current analytical techniques for column analysis can be used for columns with external FRP reinforcement, provided that appropriate material models are used for confined concrete, FRP composites and reinforcement steel. Plastic analysis for flexure, starting with sectional moment-curvature analysis and continuing into member analysis incorporating the formation of plastic hinging, provide excellent predictions of inelastic force-deformation envelopes of recorded hysteretic behaviour. A displacement based design procedure adapted to FRP jacketed columns, as well as columns in FRP stay-in-place formwork provide a reliable design procedure for both retrofitting existing columns and designing new FRP reinforced concrete columns.

Orientador: Vinicius Fernando Arcaro / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil / Made available in DSpace on 2018-08-09T14:58:15Z (GMT). No. of bitstreams: 1 Pinto_AntonioCarlosAlvarenga_M.pdf: 2870920 bytes, checksum: cffdfb27613fef6b77831bd28b0b89f3 (MD5) Previous issue date: 2006 / Resumo: Descreve-se, em forma cronológica, as etapas de planejamento, projeto e construção de um empreendimento habitacional com 351 unidades, localizado na cidade de Campinas, SP. São apresentados, também, comentários, críticas e sugestões para aperfeiçoamento dos processos construtivos adotados. Apresenta-se, ainda, a análise estrutural e dimensionamento (verificação) dos elementos estruturais de concreto armado de uma residência em dois pavimentos construída com a tecnologia objeto de estudo desse trabalho / Abstract: In a chronological order, the planning, the project and the construction steps of a residential enterprise, containing 351 units, in the city of Campinas, São Paulo, Brazil, are described. Comments, critical analyzes and suggestions are presented for the improvement of the construction process as well. Also, the paper details the structural analysis and dimensions of the structural elements of a two floor reinforced concrete residential building built under the technology proposed here / Mestrado / Estruturas / Mestre em Engenharia Civil

Performance of bridges during previous earthquakes has demonstrated that many structural failures could be attributed to seismic deficiencies in bridge columns. Lack of transverse reinforcement and inadequate splicing of longitudinal reinforcement in potential plastic hinge regions of columns constitute primary reasons for their poor performance. A number of column retrofit techniques have been developed and tested in the past. These techniques include steel jacketing, reinforced concrete jacketing and use of transverse prestressing (RetroBelt) for concrete confinement, shear strengthening and splice clamping. A new retrofit technique, involving fibre reinforced polymer (FRP) jacketing has emerged as a convenient and structurally sound alternative with improved durability. The new technique, although received acceptance in the construction industry, needs to be fully developed as a viable seismic retrofit methodology, supported by reliable design and construction procedures. The successful application of externally applied FRP jackets to existing columns, coupled with deteriorating bridge infrastructure, raised the possibility of using FRP reinforcement for new construction. Stay-in-place formwork, in the form of FRP tubes are being researched for its feasibility. The FRP stay-in-place tubes offer ease in construction, convenient formwork, and when left in place, the protection of concrete against environmental effects, including the protection of steel reinforcement against corrosion, while also serving as column transverse reinforcement. Combined experimental and analytical research was conducted in the current project to i) improve the performance of FRP column jacketing for existing bridge columns, and ii) to develop FRP stay-in-place formwork for new bridge columns. The experimental phase consisted of design, construction and testing of 7 full-scale reinforced concrete bridge columns under simulated seismic loading. The columns represented both existing seismically deficient bridge columns, and new columns in stay-in-place formwork. The existing columns were deficient in either shear, or flexure, where the flexural deficiencies stemmed from lack of concrete confinement and/or use of inadequately spliced longitudinal reinforcement. The test parameters included cross-sectional shape (circular or square), reinforcement splicing, column shear span for flexure and shear-dominant behaviour, FRP jacket thickness, as well as use of FRP tubes as stay-in-place formwork, with or without internally embedded FRP crossties. The columns were subjected to a constant axial compression and incrementally increasing inelastic deformation reversals. The results, presented and discussed in this thesis, indicate that the FRP retrofit methodology provides significant confinement to circular and square columns, improving column ductility substantially. The FRP jack also improved diagonal tension capacity of columns, changing brittle shear-dominant column behavior to ductile flexure dominant response. The jackets, when the transverse strains are controlled, are able to improve performance of inadequately spliced circular columns, while remain somewhat ineffective in improving the performance of spliced square columns. FRP stay-in-place formwork provides excellent ductility to circular and square columns in new concrete columns, offering tremendous potential for use in practice. The analytical phase of the project demonstrates that the current analytical techniques for column analysis can be used for columns with external FRP reinforcement, provided that appropriate material models are used for confined concrete, FRP composites and reinforcement steel. Plastic analysis for flexure, starting with sectional moment-curvature analysis and continuing into member analysis incorporating the formation of plastic hinging, provide excellent predictions of inelastic force-deformation envelopes of recorded hysteretic behaviour. A displacement based design procedure adapted to FRP jacketed columns, as well as columns in FRP stay-in-place formwork provide a reliable design procedure for both retrofitting existing columns and designing new FRP reinforced concrete columns.

The diploma thesis deals with the construction technological project of a polyfunctional building in Brno. The project contains schedule, cost estimate, the plan of building site equipment and the proposal for machinery. To be more specific, the work concerns the main building SO01 focusing on the stage of Berlin shoring construction and vertical load-bearing structure. The risk assessment, specialization concerning the sprinkler system and the technology maintenance using reconstruction are also included.

The thesis project wants to research the concept of Mongrel Geometries, the development of a spatial system that considering the processes of Form Finding as a design tool and their tight relationship with the model of efficiency and structural optimization, start questioning their problem/solving based procedure with the purpose of understanding which are the potentials of these methods to introduce within the built environment new atmospheric and programmatic qualities. / The intervention consists in the re-design of the Train Station and of the incorporated Bus Terminal, resolving the general connective tissue, and stimulating the public activity towards the sea side. The Terminal wants to be intended not only as a place of departure but also as an attractive place itself.