Load Tests University Clinic

Project Description

The ceilings to be investigated were covering the surgical department of the Munich outpatient clinic on Pettenkoferstraße. The ceilings were designed as steel beam ceilings with brick infill (Secura-Decken), and were built around 1900.

Procedure

It was assumed that the ceilings have a higher carrying capacity  than what is accepted under the current regulations. A single mathematical proof of the ceilings was however not possible because it can not be determined accurately enough how the structural steel beams and the brick infills work together. Therefore the actual carrying capacity would be determined through a combination of test loads and mathematical estimations.

Depending on the ceiling system, the load application occured over 1 to 4 hydraulic hoist cylinders, which were controlled centrally through a mechanical hand pump with a low piston volume. This ensured that all the hoist cylinders loaded the ceiling with the same force. A steel frame served as abutment for the application of force in the ceilings, which at about 0.5 m in length spanned the test space and induced the force over the benchings in the walls. With inductive displacement transducers, the deformation of the ceiling was determined with a resolution of 0.001 mm on the underside of the ceiling at various points.

The analysis of the test loads showed that the steel beam brick ceiling had a much higher carrying capacity than can be demonstrated mathematically by only considering the steel beams. This is due primarily to the design of a T-beam system between steel beams and brick infills. Based on the combined carrying capacity verification, it could be demonsrated for the majority of the ceiling that the required traffic loads can be supported without any use restrictions or strenghtening measures.