Detail design of the MPU Heavy Lifter

This paper gives insight into detail design of the MPU Heavy Lifter. The innovative structure is developed for offshore heavy lifting operations like removing or installing platforms. Its hull is composed of highly reinforced and prestressed lightweight concrete forming slabs and walls with thicknesses between 0.3m and 0.9 m. Information is provided on the design procedure, on the basis of design and on the design of B- and D-regions. Structural analysis is based on finite element analysis using shell elements. For design and verification of concrete sections the results are post-processed with specially developed software. For D-regions, truss and stress-field modelling supported by specialised finite element analysis is applied. The applicability of these design methods is verified with a series of small and large scale tests.

Design and experimental verification of an innovative steel–concrete composite beam

Jean-Paul Lebet, Dimitrios Papastergiou

This paper deals with the design method and the experimental verification of a new type of steel–concrete composite beam under static and fatigue loading. The connection is an alternative solution for steel–concrete composite bridges suitable for prefabrication and fast erection, while guaranteeing durability. The composite action of the beam is established through an innovative shear connection by adhesion, interlocking and friction. The resistance of the connection to longitudinal shear is based on the development of shear stresses in the confined interfaces that form the connection. The interfaces include a steel–cement grout interface and a rough concrete–cement grout interface. Confinement is provided by the reinforced concrete slab that encloses the connection. A composite beam was designed according to the design method for such type of composite beams in order to resist cyclic loading and to guarantee in the sequence its bearing capacity at ultimate limit state. The beam was initially subjected to cyclic loading and did not present signs of important damage after five million cycles. The damage on such type of connections is expressed by the development of a small residual slip in the interface which with the appropriate design stabilizes with the number of cycles. Finally the composite beam was statically loaded up to failure. The results show the capability of such a composite beam to develop its plastic moment at ultimate limit state.

Elsevier2014

Dynamic testing of a four-storey building with reinforced concrete and unreinforced masonry walls: Prediction, test results and data set

Katrin Beyer, Sarah Petry, Marco Tondelli

This paper presents the results of a series of shake-table tests on a half-scale, four-storey building with reinforced concrete (RC) and unreinforced masonry (URM) walls. Due to the lack of reference tests, the seismic behaviour of such mixed structures is poorly understood. The test unit was subjected to several runs of increasing intensity yielding performance states between minor damage and near collapse. Before the test, the expected peak table accelerations leading to different limit states were estimated using the capacity spectrum method, and the predicted values corresponded rather well to actual sustained accelerations. Next to these analyses, the paper describes the test unit, instrumentation and input motion, and comments on the response of the mixed structure in terms of damage evolution and global response quantities, such as force-displacement response and drift and acceleration profiles. The raw and post-processed data sets are made publically available, and all relevant information with regard to data organisation is described in an appendix to this paper. The test serves therefore as a benchmark for the validation of numerical models of such mixed structures. The project aims at providing a foundation for the development of seismic design and assessment methods of mixed structures, which are currently not covered by structural codes, including Eurocode 8.

Springer Verlag2015

A Contribution to the Design of Textile Reinforced Concrete Structures

Patrick Lorenzo Valeri

The reduction of green-house gas emissions is one of the global challenges that our society is facing and the production of cement plays a major role because concrete is the most used material worldwide. For every 1000 kg of cement produced, 900 kg of CO2, are released in the atmosphere. In addition, for structural concrete, the generous concrete cover, prescribed by current codes of practice, yields to robust but also to relatively heavy and massive members. Textile Reinforced Concrete (TRC) is a novel building material made of high-strength fabrics embedded in a fine grained mortar matrix. The implementation of non-corrosive reinforcement materials allows to reduce drastically the concrete cover requirements. That empowers to cast extremely thin-walled structural elements and to reduce the structural dead-load up to 90 % (with respect to conventional Reinforced Concrete). In addition to substantial material savings associated to the structure and its foundations, low-clinker-content cements can be used, since no passivation of the reinforcement is required. That, reduces further the environmental footprint and allows to build more sustainable load-bearing structures. Despite its advantages, TRC is hardly implemented in current engineering practice. On one hand there is a lack of design regulations, but on the other, there is also a shortage of construction experiences. With the aim to promote the widespread of TRC, this work addresses both hurdles at three different levels of analysis: First, the tensile response of TRC is investigated by means of an extensive experimental programme. It includes, tests on bare fabrics, the plain mortar and composite tension ties. On the basis of the experimental observations and the coaxial ring analogy, a mechanical model has been derived, allowing to predict the deformation capacity and resistance in a unified manner. That is fundamental to understand the effects of fabric-coating, impregnation, tie- and load introduction length on the load-bearing behavior at a micro-level. More complex loading conditions have been investigated at a meso-scale. Full-scale load tests of thin-walled flanged members have been instrumented with external photogrammetric measurements. These have allowed to validate and adapt the Elastic-Cracked-Stress-Field approach for TRC linear members. The method allows to model beam- and discontinuity regions in a comprehensive manner as well as predicting the response under serviceability conditions and at failure in a unified way, while accounting for both, bending and shear. Finally, the application potential of TRC is addressed at a macro-level. Starting from previous ferrocement works, different formworking materials, casting methods and connections of thin walled members have been explored. The obtained results have been condensed to design, build and erect a full-scale, demountable, prototype pavilion within a three-weeks workshop. Eventually, a proper architectural language has been derived for light-weight structures made of thin-walled TRC members. The structural design can be performed in a comprehensive manner with the Elastic-Cracked-Stress-Field approach, while the resistance of the composite can be estimated with the coaxial ring model. That contributes to the development of code-like prescriptions for TRC and its future implementation in common construction practice for sustainable structures.

EPFL2020

A Contribution to the Design of Textile Reinforced Concrete Structures

Patrick Lorenzo Valeri

EPFL2020