HOME > УЧАСТНИЦИ > Aviation and airport infrastructure > MULTIFUNCTIONAL OFFICE BUILDING №5




Bulgaria Air Meintenance LTD.


Plan 31 Ltd.,eng. Peter Rogachev


Tehnoimporteksport AD


Energoproekt Jsc. and Plan 31 Ltd., arch. Boyan Mitov



The administrative building is built as part of a certified investment project: „West Wing Extension Project: Expanding the aircraft repair & maintenance facilities of Lufthansa Technik Sofia Ltd., by the class A investor  – Bulgaria Air Maintenance, who received the prestigious award “Investor for the Year 2017” in the category „Business Expansion“.

The purpose of the newly built facility is to provide an office space for the increased number of employees as a result of the implementation of the certified project (new 165 positions are opened) and to facilitate access to all existing facilities in the aviation repair base (hangars 1, 1A, 2, 2-extension and 3). In the project, this functionality was provided by building a technological corridor with covered passages linking the existing facilities with the office building. This determines its key importance in the overall complex for Lufthansa Technik Sofia, located southwest of the main access to Terminal 2 and bordering from the north the Sofia Airport apron. The complex is located in a restricted area with special access regime. The approach to the aircraft repair base is controlled by a newly constructed checkpoint with a parking lot located south of the 5-storey administrative building.

The building consists of a basement, five  floors and roof installations. The multifunctionality of the building is determined by located therein office premises, workshops, where preparatory-and-repair activities for the airplanes service are performed, utility rooms, a canteen with a kitchen. In terms of structure and fire-protectionthe building is divided into two zones with areas of up to 1500 sq.m through a fireproof wall along its height.

The building has the following vertical division:

Underground floor - Level -1 - Utility and technical premises;

Ground floor (Level 0) - Workshops and canteen delivery;

Floor 1 (Level 1) - canteen with a kitchen;

Floor 2 (Level 2) – Offices;

Floor 3 (Level 3) – Offices;

Floor 4 (Level 4) – Offices;

Roof level (Level 5) – installation premises (boiler, HVAC, machines).

Vertical connections areprovided by two main staircases that reach all levels, positioned in the two halves of the building. In the western part of the building, where the main entrance for employees is situated, 3 passenger lifts are mounted. They provide also an accessible environment for disabled persons throughout the building, including to the roof. For the kitchen tract, a separate staircase and 2 freight elevators are provided. The kitchen is resolved as a separate site with its own entrance and a loading / unloading area, with a scissor-lift platform built into the road pavement.

The building is divided into two dynamically independent bodies through an anti-seismic joint that also crosses the foundations. The structure of the main building is mixed, consisting of prefabricated reinforced concrete elements and monolithic walls and staircases. The floor structure consists of prefabricated floor beams and panels, and at level ±0.00 where the repair rooms are located, the panels have a 2T cross section due to the higher operational loads. From the second floor to the roof of all levels are constructed Spirol type hollow floor panels. The pre-fabricated floor beams at all levels, as well as the roof beams have L and 2L cross sections, except for the beams in the area of cargo and passenger lifts, which will be monolithic. Vertical elements are pre-fabricated. The columns have a cross section 60x60 along the central axis and a cross section 50x50 along the two end axes, which participate only in the bearing of the vertical loads. For the bearing of the horizontal seismic forces, monolithic walls are placed from the building foundation to the roof structure level. They have a thickness of 30 cm, and only the "free-standing" walls at the basement level have a thickness of 40 cm. In the basement volume, an underground reinforced concrete tank with monolithic walls and roof monolithic slab at level ± 0.00 is built.

It should be noted that despite the structural complexity of the building, it was completed within the 9-month period as specified in the project schedule, which is of key importance given the fact that the work was carried out within an operating complex.

On the northern and eastern facades of the building are assembled steel structures with different functional purpose - one-storey frame structures with horizontal roof and vertical joints, bearing static and seismic loads. In two of the axes, the steel structures are three-floor frame systems with a floor-steel-concrete slab that provide a direct covered connection to the office floors with the existing hangars to the north of the newly constructed building.

On the ground floor is built the so-called "access corridor" along the entire northern facade of the building, with a clear width of 5.15 m and connected to the Interiors and Panels workshops and their preparatory premises, with two sectional doors of 3x3 m in size, for loading the workshops with materials. The corridor is equipped with several 3.60 m wide roller doors, corresponding to the analogous ones at the existing hangars 1A and 2, thus enabling the transportation of parts to and from the workshops. These communication links are covered for the hangar 1A of a newly designed shed, and for the hangar 2, the role of a shed is played by two new covered passages at upper levels that provide quick access for workers between the hangar 2 and the service building. Covered passages provide a transition between the two buildings at the level of the canteen (elevation + 4.70) and the first office level (elevation +9.30). In the eastern half of the basement of the building (elevation -4.00) are situated the dressing rooms, tailored to the number of staff and adapted for individual use, equipped with all necessary amenities - washroom, toilets and showers. At this level, workshops are also located, and separate ventilation systems are provided for the decontamination rooms. Where harmful substances are flammable, the ventilation systems are provided to be with explosion-proof fans. In the dust extraction rooms, local dirty air extractors with dust filters are provided.

In the eastern half of the first floor of the building, a canteen is provided, designed and executed to serve 450 people per shift, in accordance with the production and administrative rate of the operation of Lufthansa Technik Sofia, equipped with state-of-the-art canteen equipment with two independent service belts, three express payboxes with contactless card payment. In the western half of the floor is situated a kitchen that meets the highest class of equipment in compliance with the requirements of Lufthansa Sky Chefs, a partner of the joint venture group of the investor and owner of the base. The kitchen premises are located on two levels - ground and floor 1. The vertical communication between the levels is realized by means of a separate staircase and two cargo lifts.

Floors 2, 3 and 4 of the multifunctional building are offices  up to 200 employees per floor. Most of them are divided into two open areas - room flexibility, conference rooms, "quiet rooms" for private conversations, offices, a server room, and a hall. The natural light of the office premises is provided by the entirely glass southern facade of the building. Air conditioning and fresh air are provided through four-pipe fan coil convectors and a general-purpose ventilation intake and exhaust system. The fresh air intake and the exhaust air discharge are provided on the roof. The air supply to the office premises is provided through ceiling grilles.

The roof of the building is covered by  PVC membrane. The roof edges are finished with  metal sheets with PVC coating. Safety roof edge railing is provided. On the western part of the roof is built a "recreation area" shaped as a terrace with wooden decking. On the roof level are located cold production systems, air conditioning chambers and fans covered by special acoustic materials, in order to achieve maximum soundproofing, a boiler room for humidification of the dry outdoor air supplied to the offices during the winter and an energy center. Roofing facilities are provided with reinforced paths for revision purposes.

In the multifunctional administrative and production building is installed a BMS system which monitors and control all installations of the building infrastructure - the pumping stations, heating, ventilation and air conditioning, electrical, fire detection, fire protection, security.

The building is provided and secured for uninterrupted 24/7 operation mode through supplying reserve power provided by a diesel generator. For the needs of the whole complex an energy center is built and functioning consisting of a diesel unit and a double concrete complete transformer station (CCTS). The energy center is separated into a separate site, located in close proximity to the newly built administrative building.

With the construction of the multifunctional building, optimization of the working and administrative processes inherent to the activity of the aircraft repair base has been achieved, by the provision of sufficient office space, a separate kitchen and a canteen, ensuring to the highest extend the satisfaction of the employees and guests of the base.

By bringingthe building into operation, the necessary synergy between all the sites  on the territory of Lufthansa Technik Sofia is achieved and the opportunity for sustainable future development and growth is provided.