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Hamburg, Germany

Mauer S.,Ingenieurburo Grassl GmbH | Rockenfelder R.,Landesbetrieb Strassenbau NRW
Beton- und Stahlbetonbau | Year: 2013

In the course of the six-lane extension of the A1 motorway, the existing viaduct Einsiedelstein had to be partially renovated. It is an vault bridge built in 1938. As a basis for the planning of necessary measures of redevelopments finite element calculations were carried out taking into account the non-linear material behavior of the backfill concrete and masonry vaults for the loads of DIN technical report. The applied calculation methods allow a realistic modeling of the load-bearing behavior of historic masonry structures in the ultimate limit state and serviceability limit state. The calculation results were used for choosing a sustainable measure for the partial replacement of the vault bridge. Copyright © 2013 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

Fischer O.,TU Munich | Muller A.,BuchtingStreit AG Beratende Ingenieure VBI | Lechner T.,TU Munich | Wild M.,TU Munich | Kessner K.,Ingenieurburo Grassl GmbH
Beton- und Stahlbetonbau | Year: 2014

In May 2011 the new guideline "Nachrechnungsrichtlinie" (standard for bridge re-analysis and assessment) was recommended for application in order to implement a harmonized basis for the assessment of existing road bridges. Within the framework of a research project initiated and funded by the Federal Highway Research Institute (BASt) re-analysis results of in total 146 concrete bridges were collected and evaluated. One major goal of this project was to provide a basis for a more efficient re-analysis and an improved documentation of the results. The present paper firstly describes typical "calculatory deficits" requiring additional considerations upon completion of the so-called re-analysis stage 2. Subsequently, general recommendations for future re-analyses are being provided, advices are given in terms of the handling of deficits and a proposal is made and discussed regarding presentation and documentation of re-analysis results. Copyright © 2014 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

Mundecke E.,TU Dresden | Mundecke E.,Ingenieurburo Grassl GmbH | Mechtcherine V.,TU Dresden
Beton- und Stahlbetonbau | Year: 2015

Strain-hardening cement-based composite (SHCC) is a high-performance cementitious material which exhibits high, nonlinear deformation capabilities and strain-hardening behaviour under tensile loading. This behaviour is achieved by utilizing micro-mechanical effects which induce multiple cracking by bridging cracks with polymer fibres. The goal of the research work at hand is to acquire a deeper understanding of the interaction between steel reinforcement and SHCC under tensile loads. The mechanical interrelation between these two materials is governed by the tensile-deformation behaviour of both steel and SHCC and the bond between them as well. The material properties and their combined influence on the global and local deformation behaviour of structural members under tensile load were analysed in order to enable the sustainable, efficient design of structures made of steel-reinforced SHCC (R/SHCC). A series of large-scale uniaxial tension tests was carried out to investigate the influence of the reinforcement ratio on the deformation and cracking behaviour of R/SHCC elements. The results showed that the load bearing-deformation characteristics of the elements under tensile load is governed by the multiple-cracking behaviour of the SHCC after initial cracking. It could be concluded that the multiple cracking of SHCC enhances the load-bearing capacity of the slab in comparison to slabs made of ordinary RC and prevents the development of large cracks, even at low reinforcement ratios. © Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

Neugebauer P.,Ruhr University Bochum | Zedler T.,Ingenieurburo Grassl GmbH | Zedler T.,Hochtief Group | Pohl S.,Ruhr University Bochum | Mark P.,Ruhr University Bochum
Beton- und Stahlbetonbau | Year: 2015

The check of a sufficient crack width limitation is an essential part within the serviceability design of RC structural members. Examples from the recent past have shown that it often gets decisive for the overall reinforcement content in infrastructure projects like tunnels when the design provisions of EC2 are applied. Besides other criteria crack limitations are mainly used to increase the structures durability by protecting the applied reinforcement against corrosion. In case this corrosion protection is given by coating (galvanizing) the rebars with zinc, the corresponding requirements for allowable crack widths could be reduced from a technical point of view. However, excessive cracking has to be prevented in any case. The bond behavior of the reinforcement is the most important issue for keeping crack widths limited. In this regard, studies by other authors, e. g. [1], have identified deviations between regular and zinc-coated rebars, without deriving a quantitative ratio for the different bonding types and bar diameters. Thus, comparative experimental investigations on the bond behavior and the crack limiting effect of zinc-coated to regular reinforcements have been conducted by the authors. Theoretical approaches are derived to describe the different bond behaviors and their effects on the crack width limitation. © Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

Borowski M.,Ingenieurburo Grassl GmbH | Kapusta J.,Hamburg Port Authority
Stahlbau | Year: 2010

With the erecting of the Rethebridge, which has a span of 104.2 m, the port of Hamburg gets one of Europe's largest road bridges and Europe's largest railway bridge with two movable (spans bridge). The superstructure is divided in two parts, one for railway and one for road traffic, thus allowing an economic construction for the different loads. The size of the movable spans results in huge piers (21.7 m deep in ground) standing in Elbe's tidal area needing special anchorage measurements. The bridge's structure is composed of four truss girders, every bridge side, tapering to the middle of the bridge. At closed position, a special finger construction in the middle of the bridge allows the transfer of positive moments without any mechanical locking system. © Ernst & Sohn Verlag fü Architektur und Technische Wissenschaften GmbH & C. KG, Berlin.

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