Photo © Jean-Luc Valentin
Photo © Jean-Luc Valentin
Photo © Jean-Luc Valentin
Photo © Jean-Luc Valentin
Photo © Jean-Luc Valentin
Photo © Jean-Luc Valentin
Drawing © KSP Jürgen Engel
Drawing © KSP Jürgen Engel


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Frankfurt am Main
Hochtief Projektentwicklung GmbH

Judged by its height of just 96 meters, the WestendDuo on Bockenheimer Landstrasse is one of Frankfurt’s smaller high - rises, yet on account of its unostentatious elegance it represents a highlight in the financial center’s skyline, standing out for its ingenious ecological overall concept.

The two towers adopt the urban grids of the Westend district of Frankfurt, which meet on Bockenheimer Landstrasse. The slightly arched facades add momentum to the shape. Vertical façade elements transform two storeys into a single unit, emphasizing the slender elegance.

A novelty with regard to high-rises in Frankfurt, the publicly accessible ground floor boasts a restaurant and bars, upgrading the building and the surroundings. The mature trees on the forecourt were left untouched, welcoming visitors from a park-like piece of land.

In order to be able to be flexible in its response to future user needs, the new building has been designed to accommodate different tenant configurations. The positioning of the access shafts and the inside rooms, which are pillar free, enable the rental of small sections of up to four units per floor, as well as the creation of a variety of office configurations, from open-plan systems and team rooms, to single - person offices.

The aim of the energy concept for the Westend-Duo high - rise is a high degree of user comfort provided by comparatively low energy consumption. The natural ventilation in the rooms by means of opening wings ensures a pleasant, individually regulated climate. The dual façade minimizes heat loss and, on account of the sun screen in the space in between, prevents excessive temperatures in summer.

One of the core elements of the concept is the radiant ceiling, which in winter is fed with heated, and in summer with cooled water. This is archieved using a geothermal pump. Water at a temperature of 21°C is pumped from a depth of 140 meters and, using a heat exchanger and heat pump, guarantees a pleasant ambient temperature in both office towers all year round.

The low load - bearing ceiling depth (with integrated facilities) ensures office areas require no false floors or suspended ceilings, while affording floor- to - ceiling heights of about three meters in exceedingly flexible rooms. Load - bearing structure and building services are tightly interwoven in this slab system design. Dividing the building services in the ground plan into two groups they could be placed respectively under and above the raw slab. Rearranging the building services increases the structural height without loss of functionality.

An innovative ceiling system designed in closely coordinated planning by the architect, the structural engineers and the facility management specialists ensures optimum exploitation of the permissible height of the building. 25 standard storeys could be built with a total building elevation of less than 100 meters.

Floor area
32,700 m²


International Highrise Award 2008 – Special prize for Sustainability
Prime Property Award 2008 – 3rd prizr

Other Projects by KSP ENGEL

Hamburg Süd Headquarters
Justice and Administration Center
National Library of China
Beijing, China
Investitionsbank des Landes Brandenburg (ILB)