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A modular precast segmental bridge with thermally formed CFRP reinforcement – modularisation approach and precast concrete production Modular construction enables the serial prefabrication of structural elements and transfers manufacturing processes from the construction site to the protected environment of a precast concrete factory. In serial production with sufficient quantities, rationalisation, digitalisation and automation of manufacturing processes becomes viable and economies of scale can be utilised. In the design realisation of modular building structures, the design engineer is faced with the challenge of arranging these into sensible modules and designing robust and durable joints. This article presents a modularisation approach based on the principles of precast segmental construction and discusses the design and precast segment production for an 8.10 m long test bridge. Non‐metallic reinforcement made of carbon fibre reinforced polymers (CFRP) is used in order to create particularly material‐efficient and thin‐walled concrete cross‐sections and to avoid the risk of reinforcement corrosion. The forming of the reinforcement elements, which is currently still a technical challenge in the application of CFRP‐reinforced concrete, was realised by using recently developed processes of thermal forming. With the realisation of a modular segmental bridge with thermally formed CFRP reinforcement, the authors aim to contribute to the development of technical solutions for modular construction and demonstrate new fields of application for non‐metallic reinforcements. [ABSTRACT FROM AUTHOR]

Modular precast construction is a methodological approach to reduce environmental impacts and increase productivity when building with concrete. Constructions are segmented into similar precast concrete elements, prefabricated with integrated quality control, and assembled just-in-sequence on site. Due to the automatised prefabrication, inaccuracies are minimised and the use of high-performance materials is enabled. As a result, the construction process is accelerated, and the modules can be designed to be lightweight and resource-efficient. This contribution presents the fundamentals of modular constructions made from precast concrete components. Then, to elaborate the requirements of a contemporary modular precast construction, the historic developments are described. Further, concepts and technical processes–comprehensible to non-expert readers–are introduced to formalise the discussion about the current state-of-the-art methods. Three case studies treating ongoing research are introduced and related to the conceptual fundamentals. The research is evaluated with regard to current barriers and future directions. In conclusion, modular precast construction is able to reduce emissions and increase productivity in the sector if researchers and firms coordinate the development of suitable technologies that bring value to critical stakeholders. [ABSTRACT FROM AUTHOR]

Modular footbridges made of serially prefabricated concrete elements – Designs from DFG Priority Programme 2187 Modular building structures enable serial and automated production of prefabricated elements, which can be produced in a controlled manner in a precast concrete plant and then assembled on the construction site in a short time. This allows manufacturing processes to be optimised and new technologies of automated and robot‐assisted production to be used. Off‐site production reduces noise, dust and traffic at construction sites, and the rationalisation of processes in the precast concrete plant can minimise offcuts and waste, thus saving resources. In addition, high‐performance materials can be processed with high precision in an environment protected from the weather, so that their properties are optimally utilised and a high and consistent quality is achieved. From the design engineer, modular construction requires a comprehensive understanding and consideration of manufacturing processes as well as careful planning of all joints of the structure. The design team is faced with the challenge of designing a functional, durable and aesthetically appealing structure despite the demands of modularisation, rationalisation and production. In the design studies presented in this paper, the authors meet this challenge by applying technologies from current research projects in modular concrete construction to a consistent design scenario of a pedestrian bridge. [ABSTRACT FROM AUTHOR]

Carbon fiber‐reinforced polymer (CFRP) has proven to be an excellent replacement for conventionally used steel in the construction industry. This is especially relevant in bridge engineering, where its corrosion resistance, low weight‐to‐strength ratio, and outstanding fatigue properties can be put to appropriate use, for example, to prestress the bridge girders. These properties are a huge part of the success of prestressed CFRP bridges, which tremendously increase the structural and material efficiency and hence help facilitate the construction of slender and durable bridges. However, apart from the structural performance of the bridges, the aspect of sustainability (environmental viability, economic feasibility, and social acceptance) plays a vital role in determining the overall efficiency. Prior studies have illustrated that the CFRP reinforcements in themselves are relatively unsustainable as compared to conventional steel reinforcements. However, owing to the extraordinarily high material efficiency generally associated with structures built with CFRP reinforcements, it can be hypothesized that these are equally or even more sustainable as compared to their counterparts. In this study, an aspect of sustainability, namely, environmental impact, is addressed. As a first part of the study, cradle‐to‐gate CO2 emissions for conventional building materials and CFRP have been thoroughly reviewed and documented. Attributed to the heterogeneity of the data available for CO2 emissions from CFRP reinforcements, three scenarios (favorable, realistic, and unfavorable) were drawn up. Based on these values, a comparative life cycle assessment was undertaken for two bridge systems, namely, Rosensteinsteg II (already constructed) and an overpass over German highway A‐20 (design in process). For each bridge system, two separate variants with steel and CFRP reinforcements were considered. For Rosensteinsteg II, a reduction of approximately 28% was observed in the CO2 emissions (favorable global warming potential values for CFRP) once the steel was replaced with prestressed CFRP. A total of 18% reduction was observed for the A‐20 bridge with CFRP reinforcements. With the help of the current study, it could be concluded that, especially for bridges not experiencing heavy vehicular loads, prestressed CFRP bridges are the most environmentally feasible option. [ABSTRACT FROM AUTHOR]

Beneath the surface – Computed tomography for precast segmental bridges Industrial computed tomography (CT) allows us to look "beneath the surface" of hardened concrete components and provides high‐precision 3D measurement data from inside the component. Provided that a computer tomograph suitable for the component is available, a variety of information can be recorded in this way that was previously only accessible by destructive testing, e.g. the exact position of the reinforcement or the local accumulation of air voids in the concrete. This information is relevant for the quality of precast concrete components and can be beneficially utilized in a quality assurance system in the precast concrete plant. Particularly in the context of automation and digitalization of precast concrete production, CT quality assessment integrated into the flow production process holds great potential. In this way, for example, precast segmental bridges can be produced, where the individually quality‐assessed segments are later joined by post‐tensioning on the construction site to form bridges. With the 3D information captured by CT, it is possible to accurately analyze the variation of parameters previously covered by partial safety factors and thus rethink the safety concept for concrete. By monitoring parameter variation and subsequently reducing safety‐related material demand, a valuable contribution can be made to climate protection and the conservation of natural resources. [ABSTRACT FROM AUTHOR]