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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.

Yes / This paper reports the testing of 11 reinforced concrete (RC) two-span beams strengthened in flexure with externally bonded carbon fiber-reinforced polymer (CFRP) sheets. The beams were classified into two groups according to the arrangement of the internal steel reinforcement. Each group included one unstrengthened control beam. The main parameters studied were the position, length, and number of CFRP layers. External strengthening using CFRP sheets was found to increase the beam load capacity. All strengthened beams exhibited less ductility compared with the unstrengthened control beams, however, and showed undesirable sudden failure modes. There was an optimum number of CFRP layers beyond which there was no further enhancement in the beam capacity. Extending the CFRP sheet length to cover the entire hogging or sagging zones did not prevent peeling failure of the CFRP sheets, which was the dominant failure mode of beams tested.

The work deals with the static solution of monolithic reinforced concrete multi-purpose building, which includes a design point - supported panel, columns, flaps, underground wall and base band. Assessment of these structures in terms od first critical state -carrying capacity.

The aim of this study was to assess the strength, durability properties and corrosion resistance of concrete samples using supplementary cementitious blended materials. In this investigation, three supplementary concrete materials (SCMs) were used together with ordinary Portland Cement (OPC) to form cementitious blends at different proportions. The supplementary materials are silica fume (SF), ground granulated blast furnace slag (GGBS) and fly ash (FA). Sixteen (16) different proportions of the cementitious blends were produced. Tests carried out on concrete samples include slump test, compressive strength, oxygen permeability, sorptivity, porosity, chloride conductivity test, resistance to chloride and sulphate attack. The electrode potentials of tested samples were also observed using electrochemical measurements. Concrete specimens prepared with 10%, 20%, 30%, 40%, up to 60% of blended cements replacement levels were evaluated for their compressive strength at, 7, 14, 28, 90 and 120 days while the specimens were evaluated for durability tests at 28, and 90 days respectively. The results were compared with ordinary Portland cement concrete without blended cement. Voltage, and temperature measurements were also carried out to understand the quality of concrete. The corrosion performance of steel in reinforced concrete was studied and evaluated by electrochemical half-cell potential technique in both sodium chloride, and magnesium sulphate solutions respectively. The reinforced concrete specimens with centrally embedded 12mm steel bar were exposed to chloride and sulphate solutions with the 0.5 M NaCl and MgSO4 concentrations respectively. An impressed voltage technique was carried out to evaluate the corrosion resistance of the combination of quaternary cementitious blended cement, so as to get the combination with optimum performance. Improvement of strength, durability, and corrosion resistance properties of blended concrete samples are observed at different optimum percentages for binary, ternary and quaternary samples. The effect of cementitious blends is recognized in limiting the corrosion potential of the tested SCM concrete samples. Generally, the cementitious blends with limited quantity of SF to 10% have the potential to produce satisfactory concrete. These should however be used for low cost construction, where high quality concrete is not required. / Civil and Chemical Engineering / M. Tech. (Chemical Engineering)

This master thesis summarizes the current knowledge regarding the design and properties of glass fiber reinforced concrete products. It also deals with the design of a new concrete recipe for Dako spol. s.r.o company. There is verified effect of changes in input materials in real conditions the company to increase tensile bending strength above 20 MPa.In particular, verification of the use of building chemistry like superplasticizing additives, polymer-cement matrix or a change type or dose of glass fiber.

Aim of the final thesis is to create loadbearing prefabricated structure of building, which serve like office building and area for car-showroom, and creating static assessment of main supporting parts. For those parts will make drawing documentation of reinforcement and shapes. Computational 3D model for evaluation of internal forces is realized in Dlubal RFEM 5.07 software. For better check and comparison were create 2D spatial bar models of selected frames.

This Diploma Thesis addresses the new building of the municipal library. Building has two floors and one basement. Operation of library is divided into public and private part. In the basement there are technical facilities, storage space and archive of books. In the first floor is space for the readers and coffee bar. In the second floor is study room, conference room and offices to ensure the operation of the library. All floors are equipped with sanitary facilities and room for staff. The building is covered with flat ply roof.

The diploma thesis is focused on structural design and assessment of lookout tower. The elements of the lookout tower are made of cast-in-place reinforced concrete except for the stair flight, which is made of prefabricated reinforced concrete. The output of the diploma thesis is a structural design report and drawings of the shape and reinforcement. The calculations were performed using Dlubal RFEM 5.26.02. The drawings was processed by AutoCAD 2020 with the RECOC extension.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Strain Hardening Cement Based Composite (SHCC) is a type of High Performance Fibre Reinforced Cement-based Composite (HPFRCC). SHCC contains randomly distributed short fibres which improve the ductility of the material and can resist the full tensile load at strains up to 5 %. When SHCC is subjected to tensile loading, fine multiple cracking occurs that portrays a pseudo strain hardening effect as a result. The multiple cracking is what sets SHCC aside from conventional Reinforced Concrete (RC). Conventional RC forms one large crack that results in durability problems. The multiple cracks of SHCC typically have an average crack width of less than 80 μm (Adendorff, 2009), resulting in an improved durability compared to conventional RC. The aim of this research project is to quantify the cracking behaviour of SHCC which can be used to quantify the durability of SHCC. The cracking behaviour is described using a statistical distribution model, which represents the crack widths distribution and a mathematical expression that describes the crack pattern. The cracking behaviour was determined by measuring the cracks during quasi-static uni-axial tensile tests. The cracking data was collected with the aid of a non-contact surface strain measuring system, namely the ARAMIS system. An investigation was performed on the crack measuring setup (ARAMIS) to define a crack definition that was used during the determination of the cracking behaviour of SHCC. Several different statistical distributions were considered to describe the distribution of the crack widths of SHCC. A mathematical expression named the Crack Proximity Index (CPI) which represents the distances of the cracks to each other was used to describe the crack pattern of SHCC. The Gamma distribution was found to best represent the crack widths of SHCC. It was observed that different crack patterns can be found at the same tensile strain and that the CPI would differ even though the same crack width distribution was found. A statistical distribution model was therefore found to describe the CPI distribution of SHCC at different tensile strains and it was established that the Log-normal distribution best describes the CPI distribution of SHCC. After the cracking behaviour of SHCC was determined for quasi-static tensile loading, an investigation was performed to compare it to the cracking behaviour under flexural loading. A difference in the crack widths, number of cracks and crack pattern was found between bending and tension. Therefore it was concluded that the cracking behaviour for SHCC is different under flexural loading than in tension. / AFRIKAANSE OPSOMMING: “Strain Hardening Cement-based Composite” (SHCC) is ‘n tipe “High Performance Fibre Reinforced Cement-based Composite” (HPFRCC). SHCC bevat kort vesels wat ewekansig verspreid is, wat die duktiliteit van die material verbeter en dit kan die maksimum trekkrag weerstaan tot en met ‘n vervorming van 5 %. Wanneer SHCC belas word met ‘n trekkrag, vorm verskeie fyn krake wat ‘n sogenaamde vervormingsverharding voorstel. Die verskeie krake onderskei SHCC van normale bewapende beton. Normale bewapende beton vorm een groot kraak met die gevolg dat duursaamheidsprobleme ontstaan. Die gemiddelde kraakwydte van SHCC is minder as 80 μm (Adendorff, 2009) en het dus ‘n beter duursaamheid as normale bewapende beton. Die doel van die navorsingsprojek is om die kraak gedrag van SHCC te kwantifiseer en wat dan gebruik kan word om die duursaamheid van SHCC te kwantifiseer. Die kraak gedrag is beskryf deur ‘n statistiese verspreiding model wat die kraak wydtes se verspreiding voorstel en ‘n wiskundige uitdrukking wat die kraak patroon beskryf. Die kraak gedrag was bepaal deur die krake te meet tydens die semi-statiese een-asige trek toetse. Die kraak data was met behulp van ‘n optiese vervormings toestel, naamlik die ARAMIS, versamel. ‘n Ondersoek is gedoen op die kraak meetings opstelling (ARAMIS), om ‘n kraak definisie te definieer wat gebruik is om die kraak gedrag te bepaal. Daar is gekyk na verskeie statistiese verdelings om die kraak wydtes van SHCC te beskryf. Die kraak patroon van SHCC is beskryf met ‘n wiskundige uitdrukking genoem die “Crack Proximity Index” (CPI) wat die krake se afstande van mekaar voorstel. Dit is bevind dat die Gamma verdeling die kraak wydtes van SHCC die beste beskryf. Daar is waargeneem dat verskillende kraak patrone by dieselfde vervorming verkry kan word en dat die CPI kan verskil al is die kraak wydte verdeling dieselfde. ‘n Statistiese verdelingsmodel is dus gevind om die CPI verdeling van SHCC te beskryf by verskillende vervormings, en daar is vasgestel dat die Log-normaal verdeling die CPI verdeling van SHCC die beste beskryf. Nadat die kraak gedrag van SHCC bepaal is vir semi-statiese trek-belasting, is ‘n ondersoek gedoen waar die trek-kraak gedrag vergelyk is met buig-kraak gedrag. ‘n Verskil in die kraak wydtes, aantal krake en kraak patroon is gevind tussen buiging en trek. Dus is die gevolgtrekking gemaak dat die kraak gedrag van SHCC verskillend is in buiging as in trek.