Nijsse Ir. Schipper Ing. Everts Ir. This research was carried out in cooperation with the Dutch knowledge centre concerning foundation problems KCAF which gave me the opportunity to apply the mostly theoretical education to an actual practical problem. The success of this thesis would not have been possible without the contribution of my graduation committee.
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Nijsse Ir. Schipper Ing. Everts Ir. This research was carried out in cooperation with the Dutch knowledge centre concerning foundation problems KCAF which gave me the opportunity to apply the mostly theoretical education to an actual practical problem.
The success of this thesis would not have been possible without the contribution of my graduation committee. Many thanks especially go out to ir. R Schipper, for his support, enthusiasm and consistency, and prof. Nijsse, for his support and helpful comments. My gratitude goes out to all the contractors and engineers whom I have spoken with for all their knowledge and for providing all the information that was needed for this thesis to be complete. I would also like to thank ing. Above all, I would like to thank my parents, brothers and girlfriend, for their patience and support.
It is estimated that in the upcoming decades about of these wooden pile foundations need repairing. Problems with this type of foundation are mainly caused by wood decaying fungi, bacterial degradation and insufficient load-bearing capacity. If no measurements are taken to deal with these problems houses will undergo unacceptable settlements and become uninhabitable over time. Foundation repair is essential to prevent this from happening. Currently there are several repair techniques on the market that cost, on average, about euro per house.
Financing the repair often appears to be difficult, especially, in areas where the needed mortgage exceeds the actual value of the house. Therefore research is done, within this thesis, in search of a more cost-effective construction method. A new method for foundation repair is proposed. This method comprises of external post-tensioned tendons, placed just under the ground floor at both sides of the existing masonry partition walls, a reinforced concrete cantilever beam at the outside of the front and rear facade and new driven sectionalized tubular steel piles, filled with concrete after instalment.
In which, the tendons apply a lateral compression force, which supports, in particular, the bending forces above and the existing masonry party wall distributes the loads to the supports. The cantilever beam provides the support of the house to the new piles and also incorporates a pressure box for the anchorage of the prestressing tendons. In order to put the Prestressed Masonry Beam PMB design into perspective, comparison was made with the currently most often used, floor slab piling method, taking into account the indicative costs for foundation repair.
This, however, is a rather rough estimate and depends on the situation. Further research and design refinement will change the cost estimate either way, though it can be supposed that the construction costs will not deviate much from the indicative figures given.
It was explained that the PMB design does perform well considering costs, nuisance and sustainability. Though, a structural risk analysis is necessary to quantify the structural ability of the PMB design and more research is needed in general to be accepted as a new construction method for foundation repair. It also appears that the applicability of the design is rather limited which lowers the potential to outperform conventional repair methods.
It was concluded that, although the applicability is rather limited, the Prestressed Masonry Beam has the potential to be a more cost-effective construction method for foundation repair.
This thesis covers the invention of the new method, explores the possibility to design a reinforced or prestressed masonry wall in bending and provides a cost estimate for comparison with current foundation repair techniques.
Wooden pile foundations were used, mainly in the western part of the Netherlands, up to the s. Problems with this type of foundation are mostly caused by wood decaying fungi, bacterial degradation or insufficient load capacity. In some occasions the wooden pile foundation can be preserved by, for example, bringing the ground water level above the wooden foundation parts again. Often more drastic measurements are needed like underpinning the building with new piles and pouring a new concrete floor slab which transfer the loads from the structural masonry walls to these new piles see figure 1.
Herewith risks, nuisance and in particular costs can increase severely. Nowadays, the Dutch government and local authorities offers little possibility to either subsidize the repair or to hand out low interest loans for foundation repair. It is also difficult, if not impossible, to get, for instance, provinces, municipalities or water boards Waterschappen liable for foundation problems because a plot owner is considered responsible for its own plot and these parties often simply lack the means to act.
Hence the costs for foundation repair are most often entirely for the homeowner. Homeowners can either be housing associations that often own entire building blocks but don t have the finances for large scale foundation repair or individual homeowners for whom financing the needed repair is also often challenging.
Furthermore with today s economy, property values are declining and increasing an existing mortgage is getting more difficult if not impossible. Moreover, a property doesn t increase much in value after the repair since all the money is put underground. However, if the foundation is in poor condition the property will decrease value, hence, if no action is taken means taking big losses. Making foundation repair possible more often means a need for cheaper and more efficient construction methods which can compete with the conventional methods available.
Therefore there is a need to do research on existing construction methods in search of innovation. It is particularly important to get the costs down and the repair less impairing to the homeowners. Figure Construction of new concrete floor slab on piles Brefu, Buildings will undergo unacceptable settlements thus tilting and crack development will get worse over time. As a consequence, a thorough repair of the building envelope or even jacking of the whole building might be needed.
This means an increase in costs which eventually will probably become too high to salvage a building. Therefore the execution of foundation repair in time is essential and necessary. The current varies construction methods for foundation repair have an average cost of about euro per house Luijendijk, These high costs, the nuisance to expect, execution risks and additional costs are the reason for many homeowners to postpone or even forget about foundation repair.
This minimizes the urge for general maintenance of the building which means that entire neighbourhoods will endure pauperization eventually. Changing the way foundation repair is being executed won t happen overnight. It will take some time before new materials and techniques are accepted in the often conservative construction world. To make this possible, funds are needed to invest in research.
Not only to come up with new methods but also to validate this method to be safe and that it can compete with already existing methods. Within the existing construction methods it can however be assumed that enough research is done to get the costs down, both by contractors and engineering firms. Hence it is likely to gain the most by searching for new innovative solutions for foundation repair. Part of this thesis will explore some of these options.
Sub questions: How and with what knowledge current foundations are usually build? What foundation problems have arise over the years and how serious are they? What kinds of foundation repair methods are used? What are the advantages and disadvantages of the current construction methods? What does foundation repair cost?
What materials or combination of materials can be used for foundation repair? What are the developments regarding foundation techniques and can they be applied to foundation repair?
Herewith an existing building or a whole building block is considered which has foundation problems and where it has been shown that foundation repair is needed. Design requirements and boundary conditions will be set.
The case study should be a representative example. This can, for instance, be a block of terraced houses with an adjoining street frontage, no room for storage of building materials, different settlement behaviour, and so on. This section will primarily serve to provide some background information to clarify how the foundation problems arise and how serious the problems really are.
This will be done through a literature review. The inventory of existing foundation repair techniques and the risks, costs and nuisance that come a long. The various existing techniques can be found in the literature and will be described thoroughly. The information on risks, costs and nuisance will be obtained mostly from aggrieved homeowners, contractors and engineering companies.
Much information can also be found at the KCAF. Finding a cheaper and more efficient construction method for foundation repair and determining the feasibility. Finding a new cost-effective construction method will be the innovative and most challenging part within this thesis.
There is also extensive research needed on materials, techniques and methods. The feasibility is tested by the case study mentioned earlier. Draw a conclusion about the ability to innovate within foundation repair by comparison with the existing methods.
The findings of the extended research together with the case study should lead to answers concerning the innovative possibilities in foundation repair. The following is a description of the three separate parts.
Part 1 analysis of wooden pile foundations and foundation repair techniques The scope and boundaries within innovative construction methods will be determined in this part. It will give the outline of the report which is necessary in order to achieve a good outcome and will function as a guideline for the second part. The following parts will be analysed: - The historical use of wooden pile foundations and the problems encountered over the years.
With the result of this part the first two objectives will be achieved and this section will provide the required input for the second part. Part 2 conceptual design The requirements and boundary conditions determined in the first part will be analyzed here.
The problems and possible contradictions found shall be solved through innovation. To innovate, recent developments in materials, engineering and construction methods will be studied. A large part of the information is taken from the literature, but also interviewing fellow students, teachers and especially people in the field may contribute to finding an innovative solution.
The solutions found are then placed in a morphologic overview from which different concepts will arise. In consultation with the graduation committee and with the use of a performance matrix it will be determined which concept to choose for. This part will result in a conceptual design that will be used for elaboration in the third part. Validation of the design must be determined.
Most importantly; the design must be feasible and able to compete with existing construction methods. The comparison is done through a case study mentioned earlier. This part along with the other two parts will discuss the conclusions and recommendations.
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Transities in de bouwsector zijn nodig om de grote maatschappelijke opgaven waar we als samenleving voor staan aan te kunnen. De Bouwcampus mobiliseert partijen uit de hele keten -markt, kennis en overheid-, om in co-creatie betaalbare en breed toepasbare oplossingen te ontwikkelen. Opgedane leerervaringen worden gedeeld met de hele sector. De ambitie is dat alle organisaties voor wie het vraagstuk van belang is de oplossingen kunnen gaan toepassen. Privacyverklaring - Contact. Jouw privacy is belangrijk voor ons.