Michael de Bouw

The Development of Fireproof Construction in Brussels Between 1840-1870

Abstract Fireproof mill construction had been developed in England at the end of the 18th century. In Brussels, the first large fireproof building was constructed in 1844–1847. All at once, the backlog of 50 years was eliminated. Moreover, for Brussels, the experimental period just started. Not bound by traditions, new techniques and materials were soon adopted. The evolution of the construction history of fireproof building in Brussels is discussed by going more deeply into the construction of six buildings, erected between 1844 and 1870.

Restoration of the 1824 Wissekerke Iron Suspension Footbridge: Construction Details Revealed

The wrought iron suspension footbridge, built in 1824 at the Wissekerke Castle in Kruibeke (Belgium) is the oldest surviving chain footbridge in continental Europe. As the footbridge shifted from private to public use, the condition of the footbridge was surveyed and assessed. During restoration works, which started in the winter of 2011, new construction details were revealed. The original foundation was excavated giving insight into the applied-anchorage system of the suspension cable. The iron bridge was blast-cleaned, revealing not only its connections, but uncovering assembly and production stamps. These new findings not only broaden the insight in the construction of the 1824 Wissekerke footbridge, they also contribute to the overall knowledge of early construction in wrought iron.

Victor Horta’s Iron Architecture: A Structural Analysis

The internationally acknowledged Art Nouveau architect Victor Horta built remarkable artifacts of public iron architecture in Brussels. His projects display an innovative philosophy based on apparent iron frameworks used in a very efficient manner. As a supplement to the ample historical and architectural studies on Belgium’s most famous Art Nouveau architect, this paper puts Horta’s innovative structural practice of iron into the picture. To reach this goal, a structural analysis of four of Horta’s most interesting projects is carried out, going into the following topics: conceptual philosophy (structural typology), building techniques (shapes, connection details) and the coherence of the structural logic (structural usefulness).

Terranova, a Popular Stone Imitation Cladding: Strategies and Techniques for Restoration

At the beginning of the 20th century, the application of innovative finishes on facades became a popular phenomenon in Belgium. Decorative renders were frequently used to hide the aesthetically imperfect structure and to imitate valuable natural stone features. In order to create the appearance of French stone, ingredients such as lime, mica and crushed natural stone were added to white cement. Afterwards, the surface was scratched or scraped to shape a rough texture. As a result, a convincing ‘simili-pierre’ or ‘stone imitation’ masonry was obtained, after drawing simulated joints into the wet render layer. Today, these imitation finishes suffer in most cases from discoloration, cracks, peeling off and other damage which has completely changed the initial perception. Since knowledge is lacking concerning their composition, properties and application techniques, many questions remain unanswered within the conservation area. As a consequence, incorrect decisions may be made during restoration campaigns, which may lead to additional damages. A remarkable example of a simili-pierre render is the former commercial product Terranova, which is the focus of the research. By means of literature studies, the exploration of historical patents, laboratory analysis of representative samples and a comparative research between similar claddings, this paper proposes legitimate solutions to revitalize the Terranova finishes. It is found that both original mortar formulas and historic application guidelines are key elements which form a fundamental contribution to restore stone imitating renderwork in a sustainable way, with respect for authenticity issues.

Measuring the colour of rendering mortars

When restoring decorative mortar layers on historic façades, professionals need to determine the colour of these finishes in order to select an appropriate repair mortar. Currently, the appearance of these renders is only assessed from a subjective point of view. To match with the aesthetic aspects of the façade, contractors must constantly adjust their repair mortar composition to avoid a patchwork of different colours, which is detrimental for heritage. This time-consuming (trial-and-error) methodology can be excluded by evaluating ‘colour’ with an objective numerical approach. The challenge of the research was to define and evaluate optimal material dependent boundary conditions for measuring the colour of nonhomogeneous mortars. Four samples with different scale of heterogeneity were measured by two spectrocolorimeters, both with a diffuse illumination geometry. The results were plotted in CIE-L*a*b* colour space. By calculating the colour difference (ΔE*), the influence of measuring with or without specular component was evaluated. We discovered the minimal number of measuring points depends on the scale of heterogeneity and the aperture area. The less homogeneous the mortar sample is and the smaller the aperture area, the more unique measuring points are required. Therefore, it is recommended to choose an aperture head of 25 mm or more to reduce the number of measurements, making your work time-efficient. However, in order to obtain accurate measurements on site, a portable optical spectrum analyser can be used with a 6 mm-diameter aperture, a viewing angle of 10°, SCI mode, illumination source D65, considering a minimum of 15 unique measuring points.

Upgrading Mainland Europe's Oldest Suspension Bridge

This paper presents a preliminary structural study that looks at restoration and strengthening methods to make the 20.5m span Wissekerke bridge comply with current safety standards. Due to a lack of maintenance and deterioration over decades, as well as a function shift (from private to public use), the bridge does not conform to current European norms for pedestrian bridge design. A strengthening strategy is discussed in this paper. The strategy targets maximum public use, optimal preservation, least visual impact, as well as easy future maintenance and durability. The design preserves and restores all authentic elements (such as cast iron masts, wrought iron suspension chain, back stay and railing) and replaces the structurally inadequate non authentic deck structure with a shallow barely visible steel box girder. This girder carries its own and superimposed dead load as well as all the variable loads. The bridge is designed to guarantee appropriate dynamic behavior. The authentic suspension structure is connected to the girder through a series of vertically and longitudinally sliding connections. These connections avoid load transfer from the new structure (girder) to the authentic structure (suspension system).