Christian K. Karl

Process Analysis of Cable-Driven Parallel Robots for Automated Construction

This contribution presents an introduction to cable robots, their properties and their mechatronic design for application in automated construction. Today, most steps involved in the construction process are performed manually. Thus, the integration of automated functions demands a closer look at the production and logistic paradigms, these are the main focus of this paper. Based on case studies, the authors discuss upcoming transformations in shell production by comparing the conventional construction process with proposed processes involving cable-driven parallel robots. The focus is on bricklaying and working methods for the installation of prefabricated elements. Adaptations to site logistics and changes in work organization are also considered. A case study and sensitivity analysis based on system dynamics modeling are introduced, and the conceptual design of an experimental prototype is presented. The results of the investigations show that the use of a cable-driven robot is feasible for onsite construction, enabling automation of processes to save time and cost. The study investigates crucial parameters and the potential for cable robots in the field of construction.

Investigating the Winner's Curse Based on Decision Making in an Auction Environment

Background. The majority of bidding models, such as those developed by Friedman and Gates focus on the mark-up decision. Despite a large body of literature, particularly related to the construction industry, these bidding models largely ignore human behavior. Aim. This article has two aims. The first is to contribute to the potential use of business games to study the results of auction behavior in a construction business environment. The second is to investigate the winner’s curse and its effects on individual companies and the market. Method. The methodology for this study is rooted in game theory. The reasoning which leads to the winner’s curse is explored through a behavioral multi-actor experiment. I developed a database-driven, online multiplayer auction game which served as a laboratory experiment. The study included 42 participants. Data were collected during the game, and debriefing results were analyzed. Results. The results show that contractors suffer from the winner’s curse for a variety of reasons including their own bidding strategy, strong competition within the construction market, and inaccurate estimates of project costs. These reasons affect the behavior of contractors and the intention to win the project’s bid as well as their willingness to take risks. Conclusion and Recommendations. The approach outlined in this article contributes to decision-making research in the context of the ‘reverse’ auction low bid method. I recommend that future researchers consider second-price, sealed-bid auctions (Vickrey auctions); this type of auction is also easy to implement.

Implementation of the Model Elements

The practical testing of the previously developed models in form of simulations is demonstrated in the following for the operative level, i.e. using the project model introduced in Sect. 3.8 on page 72. Depending on the intended aims, a diversity of concepts can be realized with the help of the already developed CDL units or their subsequently generated models (Chap. 3, p. 37 ff.).

Module-Oriented Modeling Approach

The main aim of this chapter is to introduce an approach for modular simulation models. In doing so, the models should be designed in a modular way, to flexibly allow for further developments. Building on separate components, a library will be set up, allowing for new elements to be embedded in it or for the existing ones to be adjusted or extended respectively.

Selected Results of Prototypical Implementation

Based on the simulation devised in Sect. 4.1, the results of the implemented simulation experiments are introduced and discussed in the following.

Exemplary Development of a Model Library

Apart from the concept of a domain-specific SDL, which is based on the SD approach and called construction dynamic library (CDL, Fig. 3.1), a cadre of module-oriented models will be introduced. Within the CDL, three significant areas are in the central focus: (1) the construction project: Construction Project Dynamics (CPD) (2) the construction company: Construction Company Dynamics (CCD) and (3) the construction market: Construction Market Dynamics (CMD). The CDL is supposed to enable users to depict both the construction industry and all involved parties in a network of linked operational, economic and market-dynamic processes.

Öffentliche Bauaufträge - Nationale Vergabeleitlinien kompakt

Gegenstand dieses Buches ist die Entwicklung eines Leitfadens zur nationalen Vergabe von Bauleistungen durch offentliche Auftraggeber. Das Thema der Vergabe von Leistungen ist sehr komplex. Dieses Buch soll sowohl offentlichen Auftraggebern, welche sich speziell mit der Vergabe von Bauleistungen auf nationaler Ebene beschaftigen, als auch Studierenden als Arbeits- und Lernhilfe dienen. Es wird erlautert, welche Schritte im Vergabeprozess notwendig sind, auf welche rechtlichen Vorgaben sich diese beziehen und wie sie durchzufuhren sind. Zur Veranschaulichung dient ein Fallbeispiel, das exemplarische Inhalte zu den einzelnen Vergabeschritten liefert. Das Fallbeispiel behandelt die nationale Ausschreibung zur Erweiterung einer Grundschule in der kommunalen Gebietskorperschaft Gemeinde. Ziel dieses Leitfadens ist, die Arbeitsabwicklung schneller, einfacher und ubersichtlicher absolvieren zu konnen, was im Besten Falle zu der Reduzierung formaler Fehler sowie zu Zeit- und somit auch Kosteneinsparungen fuhrt.