Op vrijdagavond 2 december 2022 om 20:00 werd de Nelson Mandelabrug over de A12 bij Zoetermeer plotseling afgesloten. Dat wil zeggen, je kunt er nog wel onderdoor maar niet meer overheen. Wat is er aan de hand? En wat zijn de vervolgstappen? De voetgangersbrug werd gebouwd ter gelegenheid van de Floriade in 1992, om bezoekers de mogelijkheid te geven de A12 over te steken naar het station van de Zoetermeer Stadslijn. Zoals altijd bij floriades maakte de brug deel uit van het stedenbouwkundig plan voor de periode erna, waarin op het voormalige floriadeterrein een nieuwe woonwijk werd gebouwd. De brug is inmiddels dus meer dan dertig jaar oud. @en

Prefabricated concrete piles have been used for the foundation of bigger buildings for about a century. Often a change in function, an addition (also vertically) or another type of alteration is required, resulting in different loads on the foundation. There are several complicating factors that return regularly in these assessments. The first one is a lack of data. Often drawings are missing or incomplete, e.g. showing only pile head dimensions or maximum calculated load but not the pile length, pile tip shape or material properties. Inspection is hard and only possible for the part directly under the pile head. And a third complication is that in The Netherlands there have only been official codes for piles since 1992. Various calculation and design methods from WWII until 1985 are discussed to see if there is any consistency that might lead to an indication of the load bearing capacity of piles in The Netherlands from that era. It is concluded that design rules for the load bearing capacity of concrete pile foundations in The Netherlands have been inconsistent over time. If the original detailed geotechnical calculations and/or structural drawings cannot be found in archives then the given ultimate loads cannot only not be exceeded; even if the load on a pile is currently less than stated on the technical specifications designers are advised not to increase the load.@en

This paper discusses the project StructuralComponents 6, a continuation of the ongoing project StructuralComponents which focuses on the development of computational tools for conceptual building design beginning with Breider [1]. The goal of StructuralComponents 6 is to develop a tool for the conceptual design of mid-rise concrete buildings laterally supported by shear walls. The tool allows a user to digitally construct a prismatic, rectangular building design with a custom number and arrangement of shear walls and performs structural validation of any given design in terms of stiffness, strength and stability. The project in split into two main phases. 1) A calculation method is developed that can be applied to a flexible number and arrangement of shear walls, assuming the shear walls are connected by infinitely rigid floors. 2) The tool is implemented using Python and Grasshopper. A case study is performed to determine the applicability of the tool to real-life building design. It is concluded that the rigid-floor calculation method is adequate for the design of buildings with minimal out-of-plane floor effects (i.e. buildings with pre-cast floors) and minimal torsional effects. Through the case study, it is shown that the tool can be successfully applied to a building with a complex arrangement of shear walls. @en

Failure of residential buildings during floods is an important cause of damage and loss of life. In the case of the Netherlands, the collapse of buildings is implicitly included in current damage and mortality curves since these are generated from historical data. However, the Netherlands has not experienced destructive flooding since 1953, so damage functions for modern buildings do not exist. Therefore, this paper assesses the effect of floods on modern Dutch residences with laboratory tests and structural models in order to formulate physically-based fragility curves. The results gathered are also applicable to similarly-built masonry and cavity-wall rowhouses elsewhere. Almost half of the Dutch population live in terraced houses (also known as townhouses or rowhouses), of which the critical failure mechanism during a flood is out-of-plane bending of the load-bearing walls. Failure of these structural elements should be analysed with the pressure coefficient, Cp, instead of the currently used drag coefficient, CD, because wall collapse is more likely than displacement of the entire structure. This paper describes the quantification of both coefficients by conducting flume experiments on rectangular boxes with different geometries and orientations. Higher drag coefficients are derived from the experiments than provided by FEMA, resulting in higher hydrodynamic loads on the residences. The physical approach to evaluate the collapse of residences is exemplified with a case study of the three most common type of residences in the Netherlands. Structural analyses of their load-bearing walls subjected to a hydrostatic and hydrodynamic load perpendicular to the wall show failure due to milder flood conditions than the current damage curves do for all case study residences. A sensitivity analysis shows an important influence of wall thickness, initial axial loading of the wall, and the flood water level inside the residence.@en

This paper presents a novel approach to modelling and documenting design knowledge: to use parametric technology to explicitly store knowledge which exists in a group of people (such as a company), so that it can be reused over many projects and grow over time when more projects are designed. This approach has been applied and tested on a test case of common concrete viaducts. The outcome constitutes the first iteration of the development of a parametric viaduct design platform, aimed for architects and structural engineers. The motivation was to counter the fragmentation of the Architecture, Engineering & Construction (AEC) industry, where each discipline encapsulates different knowledge areas, which results in miscommunication and the loss of valuable information and time. The suggested methodology aims at combining the BIM principles [1] with the concepts of parametric and associative design, as well as visual programming [2] to develop a common design platform for the architect and the structural engineer. Such a platform ensures that both disciplines are working on the same design and merges their different knowledge areas into one model. The knowledge model evolves from a top-down UML diagram into a user-friendly, parametric platform for viaduct design implemented in Dynamo [3].@en

The vulnerability of buildings on coastal dikes due to overtopping wave impacts is difficult to assess. A method is developed in this paper to quantify the vulnerability of masonry buildings on a coastal dike exposed to wave overtopping. Using previous studies, the accidental loads due to the extreme wave impacts are characterized. Using the approach from Eurocode 6, the strength of masonry buildings under these loads is assessed. Results from a case study in Belgium show that masonry buildings located 10–15 m away from the seafront would suffer from localized damage, such as windows being broken under a 1000 year storm. The building would collapse under a 10,000-year storm. The method can be used to assess the safety of existing buildings on coastal dikes and to design new buildings.@en