Prefabricerade väggelement - Lunds Tekniska Högskola

Summary
Today’s construction of residential buildings is characterized by demands for shorter
construction time, lower construction costs, and higher quality. Decreasing the environmental
impact of new buildings has become a highly prioritized issue as well. These growing
demands have led to an increased need to improve building materials, techniques, and
building methods. As a consequence of these developments, there has been an increased use
of prefabricated building components and elements in the construction of residential
buildings, especially detached houses.
NCC Construction Sweden AB builds 14 detached houses and 33 terrace houses in
Gustavslund, Helsingborg. For this project NCC has chosen Combi-element that is a type of
prefabricated concrete elements. The assembly of the concrete elements is an important
activity because it affects many other subsequent activities. If reliable planning data of the
assembly activity are missing, it causes uncertainties when planning the other activities.
Today, NCC is missing updated and reliable data for the assembly of new systems such as
Combi-element and needs assistance to collect and compile data so it can be used for planning
of remaining residential buildings in the project.
The purpose of this thesis is to document and measure the manufacturing and the erection
process of prefabricated Combi-elements in order to get a detailed basis for future planning.
This would also support the identification of possible improvements regarding planning of
activities and the use of resources. Another purpose is to evaluate if the analysis methods used
in this thesis are suitable for creating data about time usage for different activities and the use
of resources.
Five activities that are included in the erection of Combi-elements have been studied in detail.
Data for these activities was collected by videotaping on-site activities during the erection of
Combi-elements for four different detached houses. The videotaping was carried out at
different time periods which included interviews with people involved with the erection
process. Different analysis methods have been used to gather detailed data about time usage
for the five studied activities and for mapping the frequency of different disturbances
occurring during erection of the Combi-elements.
A detailed view of the activities and the use of resources in connection with the erection of the
Combi-element for the four studied detached houses are described in the report. The follow up
shows on differences between the four houses regarding assembly times for each activity and
the occurrence of disturbances. A slight improvement can be seen for the latest erected house
compared to the three previously erected houses. The follow up also demonstrates that
disturbances caused by late deliveries of Combi-elements have a major effect on the
efficiency of the erection for the detached houses.
Based on carried out measurements and interviews, the thesis provides some suggestions on
how to improve the erections of the elements. The videotaping and the analysis methods have
proven to be useful tools in improving the knowledge about the process and the gathering of
data. The methods are general and can be used for all types of construction related processes.
v