Ingenieurburo Grassl GmbH

Hamburg, Germany

Ingenieurburo Grassl GmbH

Hamburg, Germany
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Seipelt D.,Ingenieurburo Grassl GmbH | Neysters T.,Ingenieurburo Grassl GmbH | Coors B.,Ingenieurburo Grassl GmbH | Grassl M.,Ingenieurburo Grassl GmbH
Stahlbau | Year: 2017

Repair works of the motorway bridge across the Süderelbe after ship impact – Recalculation, design, analysis. Due to a ship impact in 2014 on the traffic-induced road bridge Süderelbbrücke in Hamburg, a maintenance analysis had to be planned and implemented within a very short time. The weight of the impact deformed the main girder of the steel superstructure in horizontal and vertical direction to the point that, in addition to a sectional weakening in the lower boom, all stiffener elements were ripped off and thus became ineffective. However, blocking of the bridge was not possible because of the heavy traffic volume. By means of analysis of the superstructure and consideration of the existing extent of damage as well as the actual lane arrangement in combination with traffic control measures, reasonable traffic management could be arranged for both the engineer and the road user. Taking into account the above-mentioned highway traffic, a maintenance concept had to be developed and implemented, which included only a few, limited-time road blockings around the bridge. Thanks to the good cooperation of all parties involved – the builder, the operating company and the planner – we have succeeded in repairing the impact damage considerably earlier than initially assumed due to an innovative, fast and safe maintenance analysis. Copyright © 2017 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin

Sanio D.,Ingenieurburo Grassl GmbH | Mark P.,Ruhr University Bochum | Ahrens M.A.,Ruhr University Bochum
Beton- und Stahlbetonbau | Year: 2017

Computation of temperature fields on bridges – Implemen tation by means of spread-sheets. Non-uniform heating causes internal stresses in statically indeterminate systems. In bridge calculation and design, these are usually considered by linear temperature gradients. Beside these linear vertical gradients, the average temperature of the cross-section is relevant for structural design. In return, nowadays standards provide deterministic values or simplified distributions for recalculation which are based on investigations of typical structures seen as representative for the entire stock. Thus, characteristics derived therefrom do not cover local features that might be beneficial like regional ambient conditions, partial clouding or a structure's specific orientation. Actually, general temperature characteristics from codes can be substituted with local information if the temperature distribution and its key parameters are extracted from the local time-variable temperature field directly. The paper shows how transient, non-stationary temperature fields can be computed from long-term climate data by means of spread-sheet analysis. For this purpose, Fourier's differential equation of heat transfer is solved with finite elements employing boundary conditions, which reflect the ambient climate conditions. Key features of the methodology are discussed in detail, while the obtained results are strictly compared to measurement data from a temperature-monitoring of a pre-stressed concrete bridge. Computed results comply well with these measurements. Copyright © 2017 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin

Mensinger M.,TU Munich | Ganslmeier S.,Buchting Streit AG | Rengstl M.,TU Munich | Karpa M.,Ingenieurburo Grassl GmbH
Stahlbau | Year: 2016

The paper deals with current issues concerning the design of roller bearings in bridge construction. An overview of current dimensioning using normative standards in DNI EN 1337-4 and SIA 263 for roller bearings is given. Based on the choice of materials, various relationships are deduced. This article will allow the reader to critically question the current design methods and historic roller bearings can then be replaced using the current structural system © 2016 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

Fust C.,Ruhr University Bochum | Wolff M.,Ingenieurburo Grassl GmbH | Mark P.,Ruhr University Bochum | Borowski M.,Ingenieurburo Grassl GmbH
Beton- und Stahlbetonbau | Year: 2012

In a collaboration of the Agency of Roads, Bridges and Waters of the Free and Hanseatic City of Hamburg (LSBG), the Grassl Consultant Engineers and the Institute of Concrete Structures at the Ruhr-University of Bochum, a clamping device to subsequently anchor transverse prestressing bars is developed. It transfers the released prestressing forces via shear friction to clamping steel plates and then by direct compressive contact to the surrounding concrete. The device is applied to stepwise rebuild the Deelböge Bridge in Hamburg continuously ensuring an ongoing traffic on one side of the bridge during building activities. The contribution lays out the conceptual design of the bridge rebuilt, the theoretical and technical elaboration of the clamping device as well as its successful application on site. © 2012 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.

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.

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.

Mauer S.,Ingenieur Buro 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.

Column constructions are designed to safely transfer vertical loads into the ground. Hence additional horizontal loading caused by accidental loading due to explosion constitute a major challenge. The determination of the dynamic system response at variable axial loading is required to identify the dynamic effects with adequate accuracy, to understand the mechanisms and to derive the design state. It is of importance to choose a suitable beam theory in combination with an efficient solution strategy. Herein, the modal analysis with an extension for continuous systems is applied on basis of the Timoshenko beam theory. The complete solution strategy is presented, investigated, compared with other selected strategies and discussed herein. © Ernst & Sohn Verlag für Architektur und tehnische 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.

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