Cement, edition 2025/2, contains a variety of interesting articles, without a specific theme. Topics include Clubhouse Boompjes in Rotterdam, reuse of precast girders, alkali-silica reaction (ASR), dynamic properties of wide slab floors, minimum shear stress resistance, and anchorage length in footings.
Shifting Volumes Enabled by Smart Design
Structural design of Clubhouse Boompjes
Author:
ir. Alexandros Glias, Van Rossum Raadgevende Ingenieurs
Clubhouse Boompjes, consisting of two towers, is located directly on the river Maas, just a stone’s throw from the center of Rotterdam. Characteristic are the staggered and cantilevered volumes, which demanded clever structural solutions.
Reusing Girders in the A76
Study on the capacity of HNP girders for a circular viaduct (Part 1)
Authors:
ir. Maikel van Dooren, Nebest; Ing. Frank Sengers, Antea Group; Ing. Remco van Osch, Nebest
The new viaduct over the A76 at Daelderweg in Nuth is designed using existing girders from the Keizer Karel viaduct on the A9. To enable this reuse, research was conducted into the capacity of these HNP girders, including load tests up to failure. A protocol for testing shear capacity was developed to facilitate future reuse.
Mortar Connections for Precast Concrete Wall Structures (2)
Modeling full-height SSK mortar connections
Author:
dr. Ir. Dick van Keulen, Ingenieursstudio DCK
Research shows that when profiled vertical joints between precast concrete walls are loaded in shear, a mortar joint with staggered notches performs best. The behavior of this so-called SSK mortar connection was further analyzed using a compression strut approach. A model was proposed to simulate shear stiffness kv in a numerical model, and a formula was developed to determine shear capacity VRd. The findings were applied and analyzed in a slab model of a wall disk structure and illustrated with a case study.
How Harmful is ASR in Concrete Structures?
Knowledge gap (partly) filled by a new Stufib report
Author:
ir. Thomas Harrewijn, Royal HaskoningDHV
ASR (alkali-silica reaction) in concrete structures can cause concerning crack patterns and compromise structural safety. For a long time, CUR Recommendation 102 (2005) was used for the (computational) structural assessment of ASR-affected structures. However, it was conservative and not aligned with the Eurocode and was withdrawn in 2017. A Stufib study group has now produced a report offering guidance for assessing ASR-affected structures, based partly on the latest insights from the fib Model Code 2020.
Dynamic Properties of Wide Slab Floors
Tests on non-prestressed and prestressed wide slab floors
Authors:
ing. Tim Hallegraeff, Peutz B.V.; Dipl.-Ing. Afshin Abbasi, Geelen Beton B.V.
Accurate vibration calculations in buildings often require 3D finite element models, where material properties, including dynamic behavior, play a critical role. The dynamic behavior of two specific types of wide slab concrete floors was investigated, also examining the effect of cracking.
Bridge Between Tradition and Innovation
Concrete in Focus – New Aare Bridge, Aarau, Switzerland
Author:
ir. Kirsten Hannema
With a modern, technically optimized concrete bridge over the Aare River in Aarau, Switzerland, Christ&Gantenbein demonstrates how to sustainably build on the existing. The municipality required the new bridge to fit the location of the 1949 bridge and reuse its concrete piers. According to the architects, concrete offered 'a modern, cost-effective solution meeting the high demands for stability, longevity, and minimal maintenance costs.'
Retrofit First: Focus on What Can Be Done!
Column by Lonneke van Haalen – Talent of the Year (5)
The most sustainable structure is the one that doesn’t need to be built. Increasingly, there is a call to value existing buildings more. Before starting a design process, an important decision must be made: preserve, or demolish and rebuild? Structural engineers have an important role here: assessing residual value, conducting feasibility studies, and research by design.
Mirror, Mirror on the Wall
First of eight columns in Cement by a structural engineer and concept developer
Author:
Maurice Hermens, Royal HaskoningDHV
Structural safety today is like mopping with the tap open. When a leak occurs, the first reaction is often to start mopping — but you should actually fix the leak. Everyone understands that. In the real world, people seem less aware. In case of incidents, the first call is often for more supervision — but does that fix the leak?
The Young Structural Engineer – Menno Weijer (Sweco Netherlands)
In this column, we meet Menno Weijer. He shares his experiences in structural engineering and his role in one of his first projects: Roosenboom in Roosendaal.
Minimum Shear Stress Resistance
Shear strength in the next generation of Eurocode for concrete structures (3)
Authors:
dr. Ir. Marco Roosen, Rijkswaterstaat; Dr. Ir. Yuguang Yang, Delft University of Technology; Ir. Gerrie Dieteren, TNO
The new Eurocode includes an updated formula for minimum shear stress resistance, based on shear strength. New parameters such as crack roughness and steel yield stress have been added, leading to a more accurate determination of minimum shear strength. Some non-conservative assumptions were identified, and an improved formula was proposed. A comparison with experimental data collected in this study shows that the improved formula reliably determines the minimum shear strength.
Anchorage Length in Footings on Firm Ground
Practical Calculations
Author:
ing. Jorrit van Ingen MSEng RC, WSP
A common foundation method for smaller structures is footings on firm ground, where concentrated loads are transferred into the soil. The bending stresses created require tensile reinforcement at the bottom of the footing. Proper anchorage of this reinforcement is essential. Should the reinforcement end directly at the footing edge, or should it be bent or hooked? NEN-EN 1992-1-1 provides various rules for anchorage length, including possible reductions. This case study focuses on anchoring tensile reinforcement in footings on firm ground and continues from "Calculations in Practice" episode 20.
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