Problemfälle

Problem cases - Underpinnings according to DIN4123 and the scrub of new geotechnical norms

Deficits in the construction of underpinnings according to DIN 4123 and supporting excavation walls in planning and implementing are common, because the bracing is often seen as costly and only temporary necessary. In fact underpinning of a building on a neighboured property is often necessary during the construction. Additionally to the technical regards, the demands of the neighbours must be taken into account. The requirements of constructions conforming to standards are presented by the example of a structural damage that resulted from various shortcomings and mistakes in foundation ground reconnaissance, planning and construction of an underpinning. The updated DIN 4123, regulating the construction of underpinnings, is embedded within a complex work of harmonised European codes of foundation engineering. Therefrom has developed, a dense scrub of the European norm EC7, a national implementation document and the leftovers of a huge number of national codes that had been unburdened from potentially competing regulations. The challenging and extremely elaborate practical work with all new EU codes, which were published in July 2012 in the list of technical building instructions and, therefore, are implemented by the authorities, has resulted in many initiatives in Germany that look for a simplification and better usability of future codes. First results indicate that this target is achieveable.