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Excavation works in urban areas require a preliminary risk damage assessment. In historical cities, the prediction of building response to settlements is necessary to reduce the risk of damage of the architectural heritage. The current method used to predict the building damage due to ground deformations is the Limiting Tensile Strain Method (LTSM) [3]. This method is based on an uncoupled soil-structure analysis, in which the building is modelled as an elastic beam subject to imposed greenfield settlements and the induced tensile strains are compared with a limit value for the material. This approach neglects many factors which play an important rule in the response of the structure to tunneling induced settlements. In this paper, the possibility to apply a settlement risk assessment derived from the seismic vulnerability approach [1] is considered. The parameters that influence the structural response to settlements can be defined through numerical coupled analyses which take into account the nonlinear behaviour of masonry and the soil-structure interaction.

The research stage of this project is about the development of a toolkit for damage-assessment, to be used by leading people in smaller restoration-projects that lack the skills and knowledge to give proper leadership in the whole process. The subject in this case is salt-related damage in brick-masonry. In the design stage, a future use is sought for an historic 1900 fishery-warehouse in Vlaardingen. The aim is to make a flexible re-design while protecting historical values of the building and it's environment.

This study presents a first attempt to quantify tangible and intangible flood damage according to two different damage metrics: monetary values and number of people affected by flooding. Tangible damage includes material damage to buildings and infrastructure; intangible damage includes damages that are difficult to quantify exactly, such as stress and inconvenience. The data used are representative of lowland flooding incidents with return periods up to 10 years. The results show that monetarisation of damage prioritises damage to buildings in comparison with roads, cycle paths and footpaths. When, on the other hand, damage is expressed in terms of numbers of people affected by a flood, road flooding is the main contributor to total flood damage. The results also show that the cumulative damage of 10 years of successive flood events is almost equal to the damage of a singular event with a T = 125 years return period. Differentiation between urban functions and the use of different kinds of damage metrics to quantify flood risk provide the opportunity to weigh tangible and intangible damages from an economic and societal perspective.

Recent tunnelling projects have received a great amount of media attention due to settlement induced damage. Due to the simplified approach of existing risk assessment methods, a new assessment system is in development, which can account for three-dimensional structural aspects of buildings. The aim of this study is to investigate the influence of the position and geometry of masonry buildings on the development of damage, while undergoing tunnelling induced settlements. In line with previous research, three-dimensional finite element analyses are used as a tool to perform a parametric study. A parametric study consists of an evaluation of the parameters position, aspect-ratio, grouping and orientation. The position parameter is divided into three characteristics: the sagging zone, a combined settlement profile and the hogging zone. The aspect-ratio parameter is also divided into three characteristics: shallow buildings, square buildings and deep buildings. The grouping effect parameter also distinguishes three characteristics: small and large isolated buildings and grouped buildings. The orientation parameter includes seven different increasing angles of the building main axis with respect to the tunnelling axis. The maximum measured crack width in the buildings gives input for a classification of damage, according the system of Burland et al. (1977). An average trend in the damage classification indicates the sensitivity to tunnelling induced settlements of the parameters. Both during and after tunnelling, a position of the building in the combined settlement profile appears to be the most sensitive to differential settlements. Buildings far away from the tunnelling axis generally obtain no more than slight damage. Structures with a low aspect-ratio seem on average to obtain equal amounts of damage as buildings with an aspect-ratio of 1. Structures with a higher aspect-ratio are less affected, both during and after tunnelling. Grouping of the buildings seems to be an influential parameter. Small isolated buildings obtain far less damage than large or grouped buildings. In relation to the numerical analyses, the empirical Limiting Tensile Strain Method (LTSM) seems to overestimate the damage for an isolated small building, but underestimate the damage in large or grouped buildings. For buildings in the sagging zone, a building with a low orientation angle is the least sensitive to differential settlement, while the maximum measured crack width increases by increasing the angle. The difference in maximum crack width can grow to a factor 3. A building in the combined settlement profile or in the hogging zone displays opposite behaviour. Cases with low orientation angles are the most susceptible to damage, while increasing the angle to 90 degrees lowers the maximum measured crack width. The difference in results can grow up to a factor 2.

Richards Bay Port, located in the East Coast of South Africa, was built during the 1970s. Two rubble mound breakwaters were constructed to protect the deep-water entrance channel and create a sheltered area for the vessels. Since the completion of these breakwaters in 1976, they have withstood several major storms, including cyclones that have caused significant damage to the dolos armour layers. To restore their functionality, two major reparations were carried out in 1976 and 1996, respectively. In addition, a severe storm that occurred in March 2007 caused relevant damages to the breakwaters of Richards Bay Port. Their damage level was established after the survey conducted in May 2007. This survey concluded that most of the breakwaters sections had an intermediate damage, except from the South Breakwater’s roundhead, which was in failure and it required urgent repairs. Since then provisional measures have been adopted to avoid the spread of damage along the breakwater while new repair works are designed. The main objective of this thesis was to determine the most suitable design for the repair works that should be applied in the roundhead of the South breakwater at Richards Bay Port through a Quasi Three-Dimensional (3D) model testing. This was achieved by reproducing the observed damage at the structure’s roundhead in one of CSIR’s hydraulic laboratory flumes and testing three repair alternatives. These repair alternatives consisted of covering the damaged structure with new armour units. Dolos, Core-Loc and antifer cubes were the armour units used in this research. The wave basin used to conduct this research had a length of 32m, a width of 4m and an available height of 1m. A transitional slope of 1:15 that extends about 4.5m long was built inside the basin to connect the deep water with the shallower water close to Richards Bay Port. Thereafter, the seabed profile corresponding to the South East direction was constructed along the next 20m of the basin. The structure was placed at a distance of 26m from the wavemaker. Graded gravel was used to construct the core, underlayer and toe protection of the roundhead, with a nominal size of 4.2g, 4.8g and 12.2g, respectively. The existing armour layer was built using dolos of 68g and gravel that represented the broken pieces. Above this damaged armour layer, the new armour units were placed with a nominal size of 82g for the dolos, 102g for the Core-Loc and 100g for the antifer cubes. The new armour units were placed trying to replicate the placement conditions at the roundhead. A total of 8 to 9 tests were conducted per armour unit. Five wave conditions were tested with increasing significant wave heights varying from 7cm to 18cm. Two water levels were set up per wave condition (High Water and Low Water). The tested wave conditions were generated with a JONSWAP spectrum and a duration that corresponded to a 1000 waves approaching the structure. Prior to and after each test, pictures were taken from three fixed positions perpendicular to the roundhead. These images were visually compared with the Armour Track software developed by CSIR to identify and quantify the movement of the armour units. This software is based on the superposition technique and it is useful to determine the stability of the structure. For each test, the stability number and the measured damage within the reference area were estimated. Generally the movements of the units occurred along the water line. However for higher wave heights (return periods of 20, 50 and 100 years), the waves overtopped and the damage started to concentrate in an area located between the angles 120 and 150 degrees from the direction of the incident wave, until failing with the overload condition. From these experiments it followed that the Core-Loc repair alternative does not perform as good as the other two options. Although all the repair options have difficulties to achieve the placement requirements at the roundhead, this phenomenon has a larger impact in the Core-Loc armour layer because it consisted of a single layer and any unit displacement resulted in failure of the structure. Therefore repairs should be undertaken more frequently, which leads to larger maintenance costs. The remaining repair options had a similar performance, even though the resistance mechanism of dolos and antifer cubes is different. The first one resists by the interlocking between the units, whereas the antifer cubes resist by their mass. Both are placed as double armour layers and thus some damage is allowed before carrying new repair works. The main difference between them is the actual feasibility to construct the units. The antifer cubes do not have any size restriction. Therefore heavier units can be manufactured without changing the stability of the unit. However, dolos have a size limitation because of its slenderness, and right now dolos heavier than 30-tonne cannot be built. Overall it could be concluded that the repair alternative consisting of antifer cubes is the one that should be applied at this particular location due to its performance and its construction feasibility.

The fresh water supply will be more under pressure, due to the predicted effects of climate change in the Netherlands. More frequent salt water intrusion during the summer semester is caused by the joint occurrence of low river discharges and the expected sea level rise. The control of external salinity is necessary to guarantee a sufficient water quality of the main water system and so protect the fresh water inlets from the intruding saline water. Consequently, regional water systems are able to take in fresh water of the main water system to control internal salinity, through counteracting salt seepage by means of salt flushing. The control of external salinity can be realized by the implementation of measures that interfere in the main water system; e.g. by optimizing the fresh water distribution. Whether a measure will be implemented depends on the decision-making process. This study is initiated, because of the arisen discussions about the pursued fresh water policy for the drought in 2003. Salinity risk management aims to assess the cost-effectiveness of measures that focus on the fresh water supply, by means of evaluating the costs and the benefits of a measure. This study investigates the possibilities of the implementation of a risk-based approach within the present Dutch fresh water policy, which is nowadays based on a deterministic approach. A salinity risk management model is developed that basically is composed of three phases that research the following questions; i.e. 1.) How does the system of external salt water intrusion in the Rhine-Meuse Estuary function for given scenarios? 2.) What is the frequency of occurrence of external salinity? Given that external salinity occurs, what are the consequences? What is the resulting salinity risk? 3.) Is the established risk acceptable? If not, which alternative measures are able to reduce the present risk level? The developed research model is examined in a case study for the risk evaluation of external salt water intrusion in the Hollandse IJssel, in particular the fresh water inlet of Gouda that provides fresh water to the control area of Rijnland. This study concludes that a risk-based approach is implementable in the Dutch fresh water policy, but extended research is necessary to obtain more reliable exceedance frequencies of a Chloride concentration. This study developed two probabilistic models; i.e. for tide-dominated locations and river-dominated locations. A third type probabilistic model should be developed for locations that are not tide- or river-dominated. Secondly, more precise statistical analysis should be conducted after the discharge variation in course of time for low river discharges. Besides, statistical research is recommended after the variation of the probability distributions thorough the summer semester of low river discharges, high sea water level set-ups and a precipitation deficit.