COOPERATION INSIDE THE PROJECT COALITION

Due to their background in the French construction industry, CBC were used to being responsible for the structural integrity of the building. Typically, French contractors have their own bureaux d'études for structural design in house. In order to assure the quality of engineering design work undertaken by the contractor, the bureau de contrôle acts on behalf of the client, but as a member of the project coalition5. Thus the structural integrity of the building is both assured by the technical expertise of the engineers of the construction firm and of the bureau de contrôle and at lastly verified by the building itself. So assurance is given by result. The German philosophy of assuring structural integrity is the opposite of this. Actors are obliged to follow certain prescribed steps of the process and fulfill given norms and rules - assurance is given by procedure. The difference between the French and the German systems is pro-bably given ex-pression best by the fact that in France any check of the structural calculat-ion happens inside the process by a member of the project coalition and that the work on site normally is not interrupted by the examination procedure, whereas in Germany the construction firm is not involved in this part of a project. All documents (like structural calculations or drawings), have to be examined outside the process by an independent actor, who is not member of the project coalition. Building permission will not be given and the construct-ion process cannot start as long as this check has not been completed. This actor in Germany is called the Prüfingenieur. The function of the Prüfin-genieur is executed by private engineering firms, to which a special licence is given by the public authority (normally the Land). Every client is obliged to engage a Prüfin-genieur and to pay for his work. A Prüfingenieur in person normally is a very well experienced structural engineer. His task is to check the structural design and drawings and he can demand changes in them before letting them pass and construction works can start. However the function of the Prüfingenieur is not seen as an overall censor or as a "hostile" agent of the client. On the contrary, structural engineers consider this function as helpful to them. If a building is simple, the work of the Prüfingenieur is fairly a routine one, if it is difficult, it provides for the structural engineer and the construction firm the benefit of what is called "The Principle of Four Eyes". Because errors or mistakes can occur to the best professional, everybody feels better, if somebody else is checking what at last is a difficult and responsible work and can have severe consequences. Although it is not his business, quite often the Prüfingenieur informally gives a help to the structural engineer working out a structural design so that his re-marks can be considered from the very beginning - so that in fact often there is not a big difference from how a bureau de contrôle is working. Moreover engineering firms having a licence as Prüfingenieur normally also work as structural engineers, so that it is quite common, that in a building project one engineering firm is en-gaged as structural engineer and the other one as Prüfingenieur, and in the next project vice versa. So Prüfingenieure, although they act towards the single building project from outside, with respect to a local network of the construction industry are far from being outsiders. Once the works on site have started, the work of the Prüfingenieur is done - unless the client demands changes of the design. In this case he comes back on the stage, but now with a enormous increase in importance. Under the German contracting system, the construction firm as structural contractor typically works with given and checked structural calculation and construction drawings from the structural engineer (although the reality on sites sometimes differs fairly from that principal). Changes of the design can be made easily - they happen under the respon-sibility and at the expense of the client. This is of course different, if the con-struction firm is the Generalübernehmer. Now the construction firm is responsible for the design. Under the French system that causes little worry. Changes are done and checked inside the process, building permission is not dependent upon approval of the documents and works on site can - normally - go on. Under the German system the worry is only little more, if changes are minor and if the structural engineers, who worked them out, are given influence over the nature of the changes. Then the collaboration with the Prüfingenieur is easy. He gives his approval to the new structural calculation of the load (Lastabtrag) as soon as he has received it. If the structural drawings (Konstruktionszeichnungen) and the layout of formwork and reinforcement (Schal- und Bewehrungspläne) are executed after the approval of the structural calculation was given, the transfer of errors and mistakes from the structural calculation to the drawings can be avoided. When the latter are checked, the principles should be correct, and only minor corrections - if any - are demanded by the Prüfingenieur. Delays can be avoided and normally the work on site does not need to be interrupted, because every engineer involved - be they structural engin-eers or site managers - can take responsibility for the building works executed. This procedure is different if changes of the design are fundamental or frequent; if they are the result not of technical reflections, but of architectural ideas or of new functional needs of the client; if structural engineers are not asked about how to translate changed ideas into structural changes, and if only little time is given to work out structural calculation and structural drawings. But exactly this was the case with the building which was performed for Galeries Lafayette in Friedrichstadtpassage. After CBC had given up the idea of executing the structural design themselves, they first engaged a Berlin engineering firm, who performed a complete structural calculation. Although all collaboration in particular on the engineer-ing level in the project coalition was reported to have been professional, satis-fying, and cooperative, this first work was not accepted by CBC. So they en-gaged another engineering firm, situated in Düsseldorf, which performed a new structural calculation. This had of course to undergo the same check-procedure by the Prüfingenieur as the first one. Otherwise building permis-sion could not have been obtained. The same happened, when the whole climate and air condition system was changed on request of CBC, who, while the construction process was running, had decided to buy a system other than the one they had ordered originally. And it happened again, when be-cause of changes of the architectural design, perhaps due to new wishes of the client, walls had to be moved or broken through, and shafts had to be constructed where originally none were planned (Interview 15/3/96). The overall procedure of the sequence of requirement, performing and checking of changes was always the same. But the consequences each time became more severe. To change the structural calculation, and the associated structural drawings and layouts for formwork and reinforcement took time, and so did the check-procedure of the Prüfinge-nieur - but time was the resource which was least available to the project. So the way to save time, which is usual under the French system and not infrequently used under the German one, was undertaken here too - to continue working on site even if plans and drawings are not completed. But whereas under the French system this is the accepted way, under the German one it requires at least two things: a building, which is technically manageable with normal resources of engineering expertise and time, and the cooperation of everybody involved in the process. But these things the project lacked at times. The building itself was not just a building, but a means to meet the needs of a world famous architect and an international department store group. The design provided, for instance, almost no load bearing walls going from the basement to the top, and main pillars whose load bearing capacity was reduced because they were angled instead of vertical. Of course engineers and construct-ion companies are able to erect such a building, as they have proved many times all over the world. But they are severely impeded, if there are continuous changes of requirements, no consultation before decision, and not enough time to prepare site works sufficiently. So when the Generalun-ternehmer once, to avoid another interruption of the work on site, decided to take the risk and to construct some element without complete and checked drawings, it had to demolish two pillars at his own expense, thereby and loosing even more time than it intended to save (Interview 15/12/95). But even that would not have happened, if cooperation between the project co-alition and the Prüfingenieur had existed. A Prüfingenieur, even if he is not ready to give informal help to a project to reduce its time pressure, by his normal way of working is not a hindrance to the progress of the project. In the construction process for buildings, first a structural calculation of the load is made, then the structural drawings, and last the layout for formwork and reinforcement, and these three documents are logically completed as a sequence one after the other. So when the Prüfingenieur gets the first one, the structural calculation, he starts to check it. If he finds something, which requires a correction, then he informs the structural engineers. An error or mistake will then not be transferred to the other documents and time will be saved for the overall process. Experts say, that Prüfingenieure normally do so. But this was, what the Prüfingenieur engaged in the project on lot 207 apparently did not. He informed about the result of his check only when he had checked all three documents. If there was a need for correction, all three documents had to re-newed, and the works on site concerned by these documents had to stop as long as correct documents has been presented. So in fact works on site had to stop for several weeks and a fairly big sum of money was lost (Interview 5/7/94).