Lic.-avh. Luleå : Luleå tekniska univ., 2008.

Lic.-avh. Stockholm : Tekn. högskolan, 2004.

The development of productivity in the construction industry has long been at a steady state compared to the manufacturing industry. Studies have shown that, amongst other things, waste on construction sites can reach up to one third of the total production cost. This has been observed from different aspects, and change is forthcoming. This thesis aims to provide a foundation for an increased productivity at production sites of building bridges. It is primarily based on a field study at Skanska, at a bridge construction site near Grängesberg. Via continuous interviews with the whole production crew, construction workers and management, information on interference and possibilities of improvement at the work site has been documented. Moreover, Lean has been studied and attention has been brought to simple methods and approaches that can contribute to an increase of productivity. The purpose of this thesis was to inform Skanska and its team of recurring disruptions and improvement prospects, and to suggest simple methods so that future projects can be run more profitably. During the field study approximately ten disruptions have been documented, which directly interfered with the production. Most of these were due to different forms of communication failures. Late deliveries and reinforcement problems were the most common disorders. Furthermore, we have found room for improvement within the visual management, where resources and technology are available, but are not utilized to its fullest potential. In conclusion we analyzed and gave suggestions of simple methods for improvement using Lean as support, were tools like Five Why’s and SMART goals were used.

Järnvägsbron vid Årstaberg kommer när den är klar att mäta 1,4 km, här passerar över 550 tåg per dygn. Bron är en del av projektet Citybanan och kommer att fungera som en spårväxel som styr fjärr-, regional- och godståg till den gamla östra Årstabron. Pendeltågen kommer då färdas på bron över Årstaviken och in i den nya järnvägstunneln vid Södra station. Entreprenaden gick från början till danska företaget Pihl och Son som efter en del problem gick i konkurs, underentreprenören Züblin fick då ta över projektet. Med en ny platsledning gjordes en hel del förändringar på arbetsgången och arbetsmomenten. Från 4 veckor per sektion, där en sektion mäter ca 30 meter lyckades Züblin tillslut effektivisera till 2 veckor. Det speciella med detta projekt är den formvagn som används, den så kallade MSS:en (Moving Scaffolding System) som är relativt ovanlig i Sverige. Författarnas uppgift var att undersöka och utreda för ytterligare effektiviseringar samt redogöra för de effektiviseringar som redan gjorts av Züblin. För att ta reda på hur arbetsgången går till har en sektion av överbyggnaden följts under byggprocessen. Författarna har tagit del av tekniska detaljer som temperatursprickor, armering, spännarmering, betongkvalité och inte minst själva formvagnen. För att få en uppfattning granskades dokument och handlingar om projektet parallellt med intervjuer med inblandade och sakkunniga. Eftersom många effektiviseringsåtgärder var genomförda när författarna påbörjade examensarbetet hos Züblin lämnades inte mycket utrymme för effektiviseringar av tekniska åtgärder. Effektiviseringar som författarna har kommit fram till gäller främst arbetsmetoder och material där mer prefabricering på armering och formning över brostöd, användning av rullarmering och självkompakterande betong. Med tanke på att inga tester och provningar har utförts är detta spekulationer som tagits i samråd med inblandade nyckelpersoner med stor erfarenhet inom sina respektive områden. / The railway bridge at Årstaberg will measure 1,4 km when finished, over 550 trains passes by every 24 hours. The bridge is a part of the project Citybanan and will serve as a railway gear that directs the long-distance, regional- and cargo trains to the old Årstabron. The commuter trains will then travel on the bridge over Årstaviken and into the new railway tunnel at Södra Station. The first contractor was the Danish company Phil & Son, who after some struggles and problems went bankrupt. The subcontractor Züblin then took over the project. With the new site management, whole new changes were made considering the workflow and other operations. From 4 weeks per section, were one section measures 30 meters, Züblin managed to reach 2 weeks. The authors' task was to investigate for further efficiency and account for the efficiency improvements already made by Züblin. In order to receive a full understanding about the workflow on sight, every step of the process has been followed on one section of the superstructure under the construction process. The technical details have been analyzed such as temperature cracks, reinforcement, stressing and concrete quality. Documents about the project had to be examined and interviews with the involved experts and thoroughly follow the operations on site. Since many efficiency measures were implemented when the authors began this degree project at Züblin, not much space was left for technical efficiency improvements. The efficiencies that caught the attention is mostly working methods and material use where more prefabrication should be utilized considering the reinforcement and forming over pillars, use of rolled reinforcement and self- consolidating concrete. Considering no tests or try-outs have been made this is only speculations which have been discussed with the involved experts with great experience in their field.