Charles de Gaulle Plaza Office Building General Data Owner : CI CDG - Centrul International Charles de Gaulle Architectural Design : Westfourth Architecture, NY- Arh. Vladimir Arsene Strucural design : Aedificia Carpati M.P. Ltd., Bucharest - Dr. Ing. Traian Pppp, Ing. Dragos Marcu, Ing. Madalin Coman General contractor : SC Bog'Art Ltd. Structural Steel Contractor (, Shop detailing, manufacturing and erection): Canam Steel Romania Top down construction, highest steel building in Romania. Height of the building is 67.5m (18 levels above ground, 5 levels underground) Area : 38000 square meters Abstract: In Charles de Gaulle Square, Bucharest, the construction of an office building, having 5 basements, a groundfloor and 17 floors was started. The built area este 38000 sq. Meters and the total height is 67.5m ( above the ground).The resistance structure of the building was designed and will be constructed using “top-down” technology, which has been used in other countries, but not in Romania for civil buildings. This techology consists of simultaneous construction of the superstructure and infrastructure levels, starting as a reference point from the ground floor and continuing up and down, so that when the infrastructure is finished, an important part of the superstructure will be finished as well. This abstract proposes a brief presentation of this technology, presenting also the designing and construction implications from the technical and economical point of view. 1. Introduction An office building having 5 basements, a ground floor and 17 floors is beeing built in Bucharest, in Charles de Gaulle square. The depth is of 16.20m (including the raft foundation) and the height above the ground is almost 70 m. The structure is created by the SC AEDIFICIA MP SRL design team; the chief of the project is Mr.Traian Popp PhD, Engineer. For the infrastructure, our consultant is Mr.Anatolie Marcu PhD, Engineer. The checking of the project was performed by Mr.Panaite Mazilu, University Professor, PhD, Honorific Member of the Romanin Academy. Basically, top-down technology means that a building can be constructed in both directions, starting from the first basement level (or ground floor) downwards, the other basement floors being constructed at the same time with the above ground levels, so that, when the infrastructure is over, an important part of the above ground structure will be already completed.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Charles de Gaulle Plaza Office Building
General Data Owner: CI CDG - Centrul International Charles de Gaulle Architectural Design: Westfourth Architecture, NY- Arh. Vladimir Arsene Strucural design : Aedificia Carpati M.P. Ltd., Bucharest - Dr. Ing. Traian Pppp, Ing. Dragos Marcu, Ing. Madalin Coman General contractor: SC Bog'Art Ltd. Structural Steel Contractor (, Shop detailing, manufacturing and erection): Canam Steel Romania Top down construction, highest steel building in Romania. Height of the building is 67.5m (18 levels above ground, 5 levels underground) Area : 38000 square meters
Abstract: In Charles de Gaulle Square, Bucharest, the construction of an office building, having 5 basements, a groundfloor and 17 floors was started. The built area este 38000 sq. Meters and the total height is 67.5m ( above the ground).The resistance structure of the building was designed and will be constructed using “top-down” technology, which has been used in other countries, but not in Romania for civil buildings. This techology consists of simultaneous construction of the superstructure and infrastructure levels, starting as a reference point from the ground floor and continuing up and down, so that when the infrastructure is finished, an important part of the superstructure will be finished as well. This abstract proposes a brief presentation of this technology, presenting also the designing and construction implications from the technical and economical point of view.
1. Introduction
An office building having 5 basements, a ground floor and 17 floors is beeing built in Bucharest, in Charles de Gaulle square. The depth is of 16.20m (including the raft foundation) and the height above the ground is almost 70 m. The structure is created by the SC AEDIFICIA MP SRL design team; the chief of the project is Mr.Traian Popp PhD, Engineer. For the infrastructure, our consultant is Mr.Anatolie Marcu PhD, Engineer. The checking of the project was performed by Mr.Panaite Mazilu, University Professor, PhD, Honorific Member of the Romanin Academy. Basically, top-down technology means that a building can be constructed in both directions, starting from the first basement level (or ground floor) downwards, the other basement floors being constructed at the same time with the above ground levels, so that, when the infrastructure is over, an important part of the above ground structure will be already completed.
The solution is a very advantageous one, especially regarding the speed of work. A very important issue is connected with the construction of the infrastructure, compared to other widespread solutions, lowering at maximum the risks regarding the strength and stability of the neighborhood buildings, especially for buildings with deep basements. From another point of view, some complications related with the construction require a very good preparation and coordination from the main contractor, this complications being given by the pioneering character in our country. This kind of technology was used in the constructions of some metro stations in Bucharest, but it was not so complex as this one. 2. Short description of the strength system of the building
The vertical strength system of the building has three main components, the central core and the façade bracings being designed for the horizontal actions: seism and wind, the metalic columns being designed for the gravity loads.
The foundations consist of a 1.75m raft foundation, sustained by drilled piles of 1.50m diameter. The piles have been designed to sustain the 10 levels during the preliminary construction, until the raft has been completed. An unconventional solution of placing the piles not at an equal step has been used, but they have been placed under the metallic columns that represent the rigid reinforcement of the central core, this placement being a request of the construction technology. Also, three different lengths of piles (12,16 and 20 m) have been used, each one taking over the loads that appear in the execution phase, the rigidity being designed according to these lengths.
The floor has been made of main metallic beams, secondary beams – trusses, and a 12 cm thick reinforced concrete surface around the central core, and a 15 cm thick inside. In the basement the floors are of slab type, with a thickness of 35 cm.
The metallic support system is made of European and American structural shapes. The main rigidity is provided by the concrete core with stiff reinforcement having
diagonals assembled in triangular shapes. This kind of system has smaller deformations from sliding, which leads to ample hysteretic curves, with high energy consumption. The composite material system is widely used not only because of the capacity, but especially for energy dissipation for the non-linear behaviour. Also, from energy dissipation reasons both metallic bracings with K diagonals are fixed with pretension screws that ensure the energy absorption through “dry” friction. The connections have been usually made with screws. This system allows work during winter time and is recommended because it increases the system’s damping and reduces the dynamic effects of the horizontal actions.
This kind of connection beam-column or beam-beam is a connection used for taking over the bending moments. The connection is not dimensioned for the maximum capacity but for stresses obtained from the structural analysis. There are three reasons for considering the fixed connection, rather than the pinned one:
• to avoid high deformations of the floor beams; thus the floor is stiffened accordingly. • to ensure a certain over-stability, avoiding the progressive collapse in the
exceptional case of a beam’s failure. • to ensure the stiffness of the building according with the technical specifications - a
0.35% relative displacement from the height of the level of the building, even if for such a building it can go up to 0.7%. This request was imposed by the cost of the curtain wall, which means quite much as a percent of the total cost.
3. The erection of the infrastructure The building’s foundation is erected on a mixed system of drilled piles of quite large
diameter (placed under the structure’s metallic columns) and a foundation raft placed at
level 16.35 (which closes the basement’s shaft), which ensures a good transmittion of gravitational loads to the ground, and also an improved behaviour of the structure at seismic actions.
The structure’s waterproofing is ensured by continuous diaphragm walls, embedded in the impermeable layer of clay, and also by horizontal and vertical izolating layers, applied to the basement’s shaft exterior (containing the raft and the perimetral concrete walls). The construction phases of infrastructure are illustrated on sheet R1.03, comprising the following works:
a) execution of borings at approx. 1 m distance on the southern sides of the site (facing the existing structures) in order to grout the non-cohesive layer (between D = 6.00 – 19.50 depths);
b) The diaphragm wall precinct (80 cm thick, 5700 m2 total area), erected below –1.00 m under protection of bentonite slurry;
c) Barrettes of 27.31 and 35 m length, executed below –1.00 m. Together with the barrettes concreting (up tp level –16.10m) the steel pillars are fixed; they support the load of the basement floors, whereas the excavated volume up to –3.00 m is filled with ballast;
d) Bored wells (45…50 cm diameter) equipped for extracting the pore water from aquafers inside the precinct;
e) Slab floors (35 cm thick) poured on the ground, at successive depths of 3.60 m, -6.40 m, -9.20 m and –12.00 m, as well as excavation advances for each basment level; the floors are supported by structural steel pillars and, on the perimeter, suspended on the diaphragm wall (a vertical hydraulic insulation is previously applied in the contact zone of the floor and the diaphragm wall);
f) The general raft foundation, executed at –16.20 m depth on a equalizing layer and horizontal waterproofing (protected by a reinforced slab).
During the mounting phase the floors will be supported on the contour and inside on
the steel pillars of the building, which are protected against fire by a reinforced concrete casing. This way, basement floors will be 35 cm thick and will act as slab floors. Also the floor will be supported around the central core through metallic cantilevers fixed on the core’s metallic structure; this skeleton is to be included in the floor as it is finally poured.
The basement’s floors will be successively built from top to bottom, begining with the one located at –3.25 m depth. After the excavation is finished, an equalizer layer of 5cm of concrete will be spread (which in fact is provided at level –3.65 m). The equalizer layer of concrete is laid over a sheet of plastic.
On the contour the floor will be provided with “teeth’’, the temporary remaining empty spaces will be filled later, at the same time with precinct walls.
4. Advantages of the top-down system
The chosen solution was to erect simultaneously the basement levels and also the above-ground levels (known as top-down) in an area delimited by diaphragm walls, without having to pump out the ground-water; the foundation characteristics for that site, the particularities of the designed structure, and the supplemental conditions imposed by the buildings in the neighborhood (especially the underground) were taken into account.
This method has some major advantages: • the speed of execution is increased by erecting a part of the above-ground levels
(the first floor and another maximum 4 levels) at the same time with the 5 basement levels.
• the diaphragm walls are supported by the slab floors of the basement levels, which are concreted as the excavation advances. It is obvious that it is the most secure
solution regarding the stability of the talus and of the buildings in the neighborhood, the risk of unwanted events is very little.
• it is not necessary to lower the level of the ground water in the neighborhood, with absorbing wells placed around the site, which would increase the costs, and could damage the buildings in the neighborhood.
• the basement’s floors are easily executed, on the ground, without framing or other frame work for sustaining the floor.
• the works can be performed from different places with different specialized teams. For example, at the same time in the 4th basement one team can perform the excavation, in the 2nd and 3rd framing can be done, while metallic structure can be fixed in the first floor.
• as a matter of costs, it is obvious that this is a very convenient solution. 5. Conclusions
The chosen solution - for the office building in Charlles de Gaulle square – has been to erect simultaneously the basement levels and also the above-ground levels (known as top-down) in an area delimited by diaphragm walls, without having to pump out the ground-water; the foundation characteristics for that site, the particularities of the designed structure, and the supplemental conditions imposed by the buildings in the neighborhood (especially the underground) have been taken into account.
This article makes an approach to some aspects regarding the conceiving and designing of this system. When the building is finished we will prepare a much ample material in order to present, besides the above mentioned, some calculations regarding the superstructure design but especially some aspects regarding the equation itself and the correspondence between the design and the real execution of the building.
The system is secure, regarding the security of the building itself but also of the neighborhood buildings, it allows a fast execution, at convenient costs.
This top-down solution is not necessarily the best and it does not exclude the classic solutions. The decision of using one solution or the other has to be taken based on serious analysis regarding all execution aspects, from the beginning till the end, taking into account economical and technical aspects as well.
Our team suggested mixed solutions for other buildings or studies, combining whenever needed the horizontal bearings, the system of excavation in inclined talus, the system of prestressed anchors, top-down system, the anchoring of the bottom of the excavated area.
Nowadays, deep basements are used more and more often, as the building spaces in
cities become more expensive, and as many parking places are needed. We believe that we can go downwards with courage, deeper and deeper, til the limit of technical and technological possibilities and rentability. The experience of other countries show that it is possible in maximum secure conditions.
Figure 1. DIAPHRAGM WALLS, WELLS, AND FOUNDATIONS ON PILES
Figure 2. FRAMING PLAN FOR –6,05 AND –8 FLOORS,
S 60x60 Ci=83,65(-1,75)
S 60x60 Ci=82,65(-2,75)
E 30x30 Ci=-1,00
E 30x30 Ci=-1,00
C320C320
C 20
0
C247.3
C280d C280
C310
C310d
C310s
C235s
C310
C310s
C320
C320sC280
s
C310
s
C320
sC3
20
C320
sC3
20
2282
.5
P 05
P 07
P 09
P 11
P 13
P 15
P 17
P 19
PM 1
PM 7 PM 6
PM 5
PM 4
PM 3
PM 2
C310
dC3
10C3
10d
C280
P 04
A
300
PILOT TIP II d=1,50m.
PILOT TIP I d=1,50m.
PILOT TIP I d=1,50m.
PILOT TIP II d=1,50m.
730
7052652
7000.5
P 32705
4198.5
P 28
PILOT TIP II d=1,50m.
705
705
705
P 30
PILOT TIP IV d=1,50m. PILOT TIP II
d=1,50m.
705
705300
P 24373.5
P 22
P 20
PILOT TIP II d=1,50m.
P 18
I 3
PILOT TIP I d=1,50m.
P 26
PILOT TIP I d=1,50m.
P 3
PILOT TIP III d=1,50m.
P5
PILOT TIP IV d=1,50m.
PILOT TIP III d=1,50m.
PILOT TIP III d=1,50m.
PILOT TIP II d=1,50m.
328
2366
300
1959
300
300
P 36
705
P 34
PILOT TIP II d=1,50m.
655
P 38
P 39
730
705
P 33
730
P 1
PILOT TIP II d=1,50m.
PILOT TIP I d=1,50m.
PILOT TIP II d=1,50m.
I 1
P 37
P 35
300
P 31
PILOT TIP II d=1,50m.
PILOT TIP II d=1,50m.
522.
5
300
P 29
Zona injectata
Zona injectata
1. Delimitarea panourilor la executia peretelui mulat s-a facut in acord cu tehnologia propusa de executantul lucrarilor.
2. Plansa nu contine pozitia reazemelor de adincime (piloti forati) ale macaralelor -turn care vor fi utilizate de executant si nici pozitia pilotilor de incercare.
3. Conditiile de injectare a terenului (intre adincimile aprox 6 si 20 m) pe laturile exterioare axei A vor fi definitivate dupa realizarea unor injectii de proba in zona precizata pe plansa.
4. In afara incintei de pereti mulati se vor executa trei foraje (cu diametrul d > 10 cm si adincimea L = 15 m) echipate pentru urmarirea nivelului apei subterane.Amplasarea lor se va face, cu avizul proiectantului, in functie de organizarea de santier.
5. Pilotii se betoneaza cu 80 cm. mai sus de cota superioara finala (respectiv -15.30), portiune de beton posibil contaminata care se indeparteaza prin spargere inainte de turnarea radierului.
6. Pilotii se vor fora sub protectia noroiului bentonitic.
7. Pilotii sunt calculati pentru ipoteza de incarcare cu 5 subsoluri, parter si etaj 1 complete, etaj 2 + etaj 3 numai structura metalica, in acord cu tehnologia de executie propusa de antrepenorul general.
8. Sunt prevazute doua incercari de proba a pilotilor pana la 1000 t f : - un pilot cu L=20m. - un pilot cu L=16m. Capacitatile portante ale pilotilor sunt estimative. Ele pot fi confirmate sau nu de catre incercarile de proba.
9. In urma incercarilor de proba se va face o reevaluare a capacitatii portante cu posibile implicatii asupra lungimii tipului IV de pilot si /sau prin prevederea unei tehnologii cu mai multe nivele de constructie executate pana la realizarea radierului.
10 La cerinta executantului a fost schimbata numerotarea panourilor: Planul - R1.08a - Armare pereti mulati. Panou de colt interior P 25.Detalii I.- se citeste - Armare pereti mulati. Panou de colt interior P 31.Detalii I. Planul - R1.09a - Armare pereti mulati. Panou de colt interior P 25.Detalii II.- se citeste - Armare pereti mulati. Panou de colt interior P 31.Detalii II.
Planul - R1.10 - Armare pereti mulati. Panou de colt P 09.Detalii I.- se citeste - Armare pereti mulati. Panou de colt P 03.Detalii I. Planul - R1.11 - Armare pereti mulati. Panou de colt P 09.Detalii II.- se citeste - Armare pereti mulati. Panou de colt P 03.Detalii II.
Planul - R1.12 - Armare pereti mulati. Panou de colt P 19.Detalii I.- se citeste - Armare pereti mulati. Panou de colt P 25.Detalii I. Planul - R1.13 - Armare pereti mulati. Panou de colt P 19.Detalii II.- se citeste - Armare pereti mulati. Panou de colt P 25.Detalii II.
Planul - R1.15 - Armare pereti mulati. Panou de colt P 08.Detalii I.- se citeste - Armare pereti mulati. Panou de colt P 14.Detalii I. Planul - R1.16 - Armare pereti mulati. Panou de colt P 08.Detalii II.- se citeste - Armare pereti mulati. Panou de colt P 14.Detalii II.
Planul - R1.17 - Armare pereti mulati. Panou de colt P 28.Detalii I.- se citeste - Armare pereti mulati. Panou de colt P 34.Detalii I. Planul - R1.18 - Armare pereti mulati. Panou de colt P 28.Detalii II.- se citeste - Armare pereti mulati. Panou de colt P 34.Detalii II.
Planul - R1.19 - Armare pereti mulati. Panou de colt P 16.Detalii I.- se citeste - Armare pereti mulati. Panou de colt P 22.Detalii I. Planul - R1.20 - Armare pereti mulati. Panou de colt P 16.Detalii II.- se citeste - Armare pereti mulati. Panou de colt P 22.Detalii II.
Planul - R1.21 - Armare pereti mulati. Panou de colt P 32.Detalii I.- se citeste - Armare pereti mulati. Panou de colt P 39.Detalii I. Planul - R1.22 - Armare pereti mulati. Panou de colt P 32.Detalii II.- se citeste - Armare pereti mulati. Panou de colt P 39.Detalii II.
* Panourile de pereti mulati au fost detaliate conform panotajului prezentat in planul R1.01e.Datorita conditiilor din amplasament succesiunea de executie a peretilor mulati si implicit planul de panotare s-a schimbat. Detaliile se pastreaza ca principiu, iar executantul va face modificarile necesare.
ROST DE TURNAREZona superioara a rampei se toarna( dupa efectuarea sapaturii locale) in acelasi timp cu planseul superior.Zona inferioara se toarna, dupa excavarea nivelului inferior, inaintea turnarii planseului inferior.
-Injectarea stratului 2 pe laturile exterioare axei A-Excavatii cota -1.00 si -3.00 ; - Executie perete mulat perimetral-Executie piloti in zona centrala si lansare stilpi (20 buc)
F A Z A 1
HD 400 x 314Stilp
-8.50
Zona injectata
Cadru de calare
Grinzi ghidaj-0.20
-2.00
-6.00
-8.50
-19.50
-22.50
-24.50
Grinzi ghidaj-1.00
Perete mulatb = 80 cm
Umplutura
Argila prafoasa
Nisip cupietris
Argila
Nisip
Argila
1
2
3
4
3'-27.00
(NH)
Pilot forat Ø150cm
Umplutura ( balast )
-3.00
StilpHD 400 x 421 HD 400 x 421
Stilp
-1.00
Grinzi ghidaj
Perete mulatb = 80 cm
-27.00
1 : 1
-0.20
-40.00
(NH' )-18.50
Gol pentru executie
-14.45
-16.35
( Nivel superior radier)
( Adincimea maxima a excavatiei )
( Nivel maxim mentinut )
Hmax = 2.50
Q Q
0
1
2
3
0
1
2
3
F A Z A 4- Excavare sub plansee - dala ; - Betonare succesiva plansee -dala cotele : -6.05 ; -8.85 ; -11.65-Realizarea nivelurilor supraterane ( max P+4 ) ; Excavare cota -14.00 si montare sprait cota -13.70 (vezi plansa F2)
( in axa "B5" )
-0.20
-2.00
-6.00
-8.50
-19.50
-13.70
±0.00
-3.25
-6.05
-8.85
-11.65
-18.50
(NH )
(NH' )
-0.20
-2.00
-6.00
(NH )-8.50
-19.50
Figura 6. EXECUTION PHASE 5
5 5
(NH )-8.50
±0.00
-3.25
-6.05
-8.85
-11.65
-14.45
-0.20 -0.20
-8.50 (NH )
F A Z A 5- Excavatii cota -16.35 ; Executie beton de egalizare si hidroizolatie orizontala si verticala ( cota -14.00) -Executie radier ; -Demontare spraituri cota -13.70 continuare hidroizolatie verticala si betonare pereti perimetrali, pereti structurali interiori si stilpi metalici.
-16.35
Figure 7. DETAILS OF FIXING THE METALLIC COLUMNS ON THE PILES