NEDERLANDSCHE MIDDENSTANDSBANK, 1979-1987

Amsterdam, The Netherlands

Alberts & Van Huut

Description

Organic functionalism is the key to this large banking complex in south Amsterdam. The building is intended to provide a friendly and healthy working environment full of light, water, sun, plants, and art. Not incidentally, Nederlansche Middenstandbank (NMB) was the world’s most energy-efficient building at the time of its comple­tion. The complex consumes less than one-tenth the ener­gy of its old headquarters and one-fifth that of another new bank in the same neighborhood. A few years after its completion, the new home had transformed the institu­tion’s image from stuffy to progressive and allegedly dou­bled its business. It also captured and maintained the 2500-person workforce’s hearty endorsement and lowered absenteeism by 15 percent. All this was accomplished at a cost of just 3 percent over conventional examples of other contemporary buildings in Holland.

Ten rambling, medieval-style office towers slope inward from the street. Their brick walls and operable win­dows surround small interconnected floor plates. Visual scale is reduced by varying the height of each mini-tower. The narrow depth and fragmented shape of the office floors allow for full penetration of daylight. At the towers’ base is a 301,280 ft2 (27,976 m2) compound of parking garages and storefronts surrounded by pedestrian plazas and gardens. Circulation is organized along a midlevel corridor resting 16.4 ft (5 m) high on top of the podium. This marble-floored corridor, an interior street, meanders 1066 ft (325 m) across the 10.8 acre (4.3 hectare) site, con­necting the office blocks, opening into their full-height skylit atriums, and tying together their open stairwells.

TABLE 11.3 Fact Sheet
Project	Building Name Client City Lat/Long/Elev	Nederlandsche Middenstandsbank NMB, now International Netherlands Group (ING) Bank South Amsterdam, The Netherlands 52.3 N 4.8 E / 7 ft (2.1 m)
Team	Architect Structure Services Interiors Building Physics Contractor	Alberts & Van Huut Raadgevend Ingenieutsboreau Aronsohn Technisch Adviesbureau Treffers Baarn Theo Crosby, Pentagram Design Ltd. Adviesbureau Peutz & Associes Bouwcombinatie
General	Time Line Floor Area Cost	1979-1982 design phase, August 1983 construction begins, April 1987 completion. 538,193 ft2 (49,975 m2). Total Costs for green technologies: $865,200 (1996). Total Costs: $53.8 million (1996). Cost/SF: $100 (1996) ($200/SF with furniture, fixtures, and equipment 1996). Site Acquisition Costs: $4.9 million (1996). Site and Building Construction Costs: $49 million (1996) average.
Site	Site Parking	10.75 acres (43,500 m2), of which 7.2 acres (29,000 m2), or 67%, are built on. 750 cars, 300,000 ft2 (28,000 m2).
Structure	Stories Plan Foundation Vertical Members Horizontal Spans	Six to nine floors of 9.1 ft (2.8 m) typical height above two parking/service levels. Ten pentagram plan towers connected by a 1066 ft (325 m) long S-shaped pedestrian street, all resting above a two-level podium of parking and service spaces. Each of the ten slanted wall towers is organized around a central light well. Not published. Precast concrete panels of 7.1 in. (180 mm) thickness. Poured-in-place concrete slabs of 11.8 in. (300 mm) thickness.
Envelope	Glass and Glazing Skylights Cladding Roof	Double glazing with automatic external louver sun blind and interior roller blind. Transom windows are oper­able by occupant. Pyramidal glass. 4.3 in. (110 mm) molded brick exterior on precast concrete lintels, 3.4 in. (8.5 mm) rock wool, 7.1 in. (180 mm) precast concrete. Seamed metal.
HVAC	Equipment Cooling Type Distribution Duct Type Vertical Chases	Two gas/diesel-driven 450 kW generators produce electricity and heat. Two 206-ton absorption cooling systems running on heat from electrical generators. One electrically driven 267-ton chiller provides backup. Vertical shafts. Not determined. Located in core of each tower.
Interior	Partitions Finishes Vertical Circulation Furniture Lighting	Open plan office spaces. Artwork and crafted installations. 21 elevators in total complex. By client. Custom accent lighting and ambient lighting in public zones.

precast concrete lintels, 3.4-in (8.5-mm) rockwool insulation. Two gas/diesel driven 450 kW generators produce electricity and heat. Two 206-ton absorption cooling systems run on waste heat from the electrical generators. One electrically driven 267- Figure 11.12 Anatomical section. ton chiller provides back-up.

A walk along this pedestrian avenue passes theaters, large conference rooms, shops, a library, and four restaurants. Works of art are designed and built into the public spaces at every turn, along with plants and “flow sculpture” chan­nels of water streaming through the building from the rainwater collection system.

At the top of each office tower is a combined skylight, mechanical room, and solar water heating system. The mechanical services work with the open shaft of the atri­um towers to provide heat recovery ventilation in the win­ter and stack-effect exhaust in the summer with a cooling assist from night ventilation.

Program

Client

At the beginning of this project in 1978, Nederlandsche Middenstandsbank (NMB) was the fourth largest bank in Holland. Having outgrown its old headquarters, the NMB executive board appointed an internal working group from within its real estate development subsidiary, MOB, to oversee the design and construction of a new complex.

The MOB committee worked in tandem with a strongly empowered workers’ council. In the Netherlands and several other European countries, such worker groups have authority to vote on many managerial decisions. Furthermore, building codes are written to enhance the quality of the working environment—amenities such as daylight and natural ventilation are mandated. The coun­cil’s oversight even included a voice in the selection of the bank’s architect and design team, the new bank location, and details of all design decisions affecting the work envi­ronment.

Brief

Collectively, the bank team laid out its aspirations for the building with intentions of both changing the bank’s pub­lic image and providing a progressive workplace. Beyond elevated standards of efficiency and flexibility, the new headquarters would integrate art, natural materials, sun­light, water, and quiet ambience. The workers’ council had its own set of criteria. Its members principally asked for inclusion of health considerations, such as favoring pleas­ant, open stairways and fewer elevators. They also empha­sized contact with the outdoors and abundant interior daylight.

After interviewing and receiving proposals also from Herman Hertzberger, Haans van Beck, and Ton Alberts, NMB and its workers’ council decided on Alberts & Van Huut. They agreed that a collaborative multidisciplinary team would be formed and required that all design deci­sions be understood and processed unanimously. As the team was brought together with the usual expertise of engineering consultants and construction management, it was to include two special elements. The first was a build­ing physics consultant. The second, surprisingly enough, was a group of 22 artists who were to collaborate in all phases of the design and construction.

Site

A location 10 km south of central Amsterdam was chosen for the project. The vicinity, known as the “Bijlmermeer” district, was dominated by 1960s high-density mid-rise housing, and many of the bank’s staff lived nearby. The

Amsterdam Poort shopping center is located on the immediate south side of the site. Most of the other sur­rounding structures are office buildings. In general, the area had acquired a mediocre reputation and was in dete­rioration. Finally, as one might expect in Holland, the building site had to be reclaimed from rising water. For NMB, this was accomplished by filling an existing lake.

Climate

The cool, wet climate of Amsterdam affects a large office building like NMB differently than it does a small struc­ture like Benthem & Crouwel’s Experimental House at Almere (See Chapter 9 for case study #20 and climate syn­opsis). Heat gain from internal loads in buildings like NMB are apt to require mechanical cooling in some zones, even during periods of very cold weather. On the other hand, it is unlikely that small buildings in Amsterdam would ever need more cooling than an open window would provide. Refer to the section on surface-load-dom­inated versus internal-load-dominated buildings and their respective balance points in Chapter 3.

With extreme temperatures below 10°F (-12°C), there are periods of the year when all areas with perimeter expo­sure in any Amsterdam building will need heat (see the discussion of thermal zoning in Chapter 3). Especially where generous areas of glass are used to achieve high day – lighting levels, the outside perimeter of the building will loose more heat than is being produced by people, lights and equipment located in the same general floor area. Deep-plan buildings, however, often have interior zones away from outside walls and thus have no envelope expo­sure. The only thermal sensitivity these internal zones have is the load incurred by replacing exhausted indoor air with outside ventilation air. Consequently, deep-plan buildings frequently have some thermal zones that require cooling regardless of outdoor temperature or internal loads.

Deep-plan buildings sometimes have perimeter zones in the heating mode and interior zones in the cooling mode at the same time. Heating and cooling can also hap­pen simultaneously in large surface-load-dominated buildings — for example, if solar radiation is overheating the sunlit orientation while the shaded side of the building is still underheated.

Intention

Design Team

Ton Alberts (1927-1999) was born in Belgium and studied at the Higher Technical School and then at the Ecole des Beaux-Arts, Paris. He finished his education at the

Academy of Architecture in Amsterdam and taught there for more than 20 years. In 1963 he established his archi­tectural practice, Alberts Architectenbureau. In the fall of 1993, Alberts was appointed to the Erasmus Chair of Dutch Civilization and Culture at Harvard.

		Jan.	Feb.	Mar.	Apr.	May	June	July	Aug.	Sept.	Oct.	Nov.	Dec.	Year
	Degree-Days Heating	840	778	695	548	342	197	117	106	215	421	628	768	5663
Temperature	Degree-Days Cooling	0	0	0	0	6	19	32	28	3	0	0	0	83
Extreme High	57	61	70	80	84	90	90	93	83	77	64	59	93
Normal High	41	42	48	53	61	66	69	70	64	57	48	44	55
Normal Average	38	37	43	47	54	59	62	62	58	51	44	40	50
Normal Low	34	32	37	40	46	52	55	55	51	46	39	36	44
	Extreme Low	3	6	18	25	30	37	39	32	36	30	20	7	3
	Dew Point	35	33	38	40	46	52	56	56	53	47	41	37	44
Humidity	Max % RH	91	91	92	90	87	89	90	91	93	93	92	92	91
Min % RH	86	79	74	66	62	66	68	65	72	78	85	88	74
% Days With Rain	73	56	71	64	64	66	65	62	68	72	75	77	67
	Rain Inches	3	2	4	2	2	2	3	2	3	4	3	3	32
Sky	% Overcast Days	42	36	35	25	21	23	19	15	21	27	35	41	28
% Clear Days	7	12	9	10	8	6	6	9	8	7	6	5	8
Wind	Prevailing Direction	S	E	WSW	N	N	W	W	W	SSW	S	SSW	SSW	W
Speed, Knots	11	11	15	10	9	9	10	10	10	9	13	12	11
Percent Calm	0	1	1	1	1	1	1	1	1	1	1	1	1
	Rain	22	17	21	19	19	20	20	19	21	22	23	23	245
Days Observed	Fog	18	19	19	17	18	18	17	20	20	20	19	20	225
Haze	13	17	17	17	18	17	15	16	16	15	11	12	185
Snow	6	7	4	2	0	0	0	0	0	0	3	5	27
Hail	1	1	1	0	0	0	0	0	0	1	1	1	7
Freezing Rain	1	0	0	0	0	0	0	0	0	0	0	1	2
	Blowing Sand	0	0	0	0	0	0	0	0	0	0	0	0	1

table 11.4 Normal Climate Data for Amsterdam

Max Van Huut was born in Indonesia in 1947. He moved to Holland at the age of ten and, like Alberts, later studied at the Higher Technical School before attending the Academy of Architecture in Amsterdam. Van Huut became a partner in Alberts’s practice in 1987. Together, Alberts and Van Huut completed some 40 town planning projects and about 50 multifamily residential works including more than 10,000 units. Their work also includ­ed hundreds of individual houses and several office build­ings, as well as some 30 retail and institutional facilities.

philosophy

Ton Alberts suffered from poor health in his early adult years and eventually turned to alternative and esoteric practices in search of a cure. This experience led him to a nature-centered principle of beliefs and ultimately to his life pursuit in design. Both Alberts and his partner, Van Huut, labeled their ultimate goal “organic functionalism.” Elements of the organic philosophical stance have been reinstituted through popular culture in recent years by revitalized interest in alternative medicine and “New Age” thinking. Although the success of Alberts & van Huut’s theories as applied to architectural practice are undeni­able, the particulars of their fringe attitudes frequently invited criticism.

Intent

Alberts believed that NMB, like other banks, should exist to serve society. He worked to provide for both the public and the individual through “friendliness, warmth, and aes­thetics.” The notions of organic functionalism he adopted from Rudolf Steiner emphasized the personal experience of space through its geometry and materials. Right angles are not part of this naturalistic expressionism. Nor is the total separation between indoor environment and natural surroundings. These morphogenic principles of organic design give precedence to discovering form in nature. The idea is that natural solutions will always produce an effec­tive result through participation in the environment. Artificial solutions, on the other hand, will always require more and more maintenance for an ever-diminishing return. The common example cited is organic farming versus intensive agricultural practices.

Starting perhaps with D’Arcy Wentworth Thompson (1860-1948) and his book, On Growth and Form (1945), morphological thinking gained modern followers through the growth of environmental movements. In the work of Alberts and Van Huut, the imitation of nature is used to determine and configure the functional systems of a build­ing. In their case, however, organic functionalism goes beyond employing biological processes to produce spon­taneous form. Their design for NMB is certainly a state­ment about their social program of placing people at the center of design. But it also ventures into sacred geometry, number magic and mystical assertions about the curative powers of architectural form. References to the pentangle

Amsterdan, Netherlands Dry-Bulb Temperature, °F Figure 11.15 Bin data distribution for Amsterdam. Concentric areas of graph indicate the number of hours per year that weather conditions nor­mally occur in this climate. Similar to elevation readings on topographic maps, highest frequency occurrences of weather are at the center peaks of the graph. (Data sources: Engineering Weather Data, typical meteoro­logical year (TMY) data from the National Climatic Data Center, and the ASHRAE Weather Data Viewer from the American Society of Heating, Refrigerating and Air-Conditioning Engineers.)

for example, border on the occult or at least the intrigue of alchemy. The five-sided figure and its internal corners of nine degrees are repeated in the complex wherever possi­ble. On the other hand, similar fascinations with the pen­tagon can be found in the drawings of Leonardo da Vinci and Tyco Brae, in which an extended human figure is cir­cumscribed by a pentangle with the planets at the five points and the moon centered anthropocentrically on the genitalia.

Critical Technical Issues

Inherent

The project brief was cooperatively established by the cor­porate client and the bank staff, so both a top-down and a bottom-up philosophy were ingrained in the program. Such duality may pose questions about the potential dif­ferences between an energy-efficient building and one where worker comfort is top priority. This issue often becomes a choice between compact, efficient boxes that are introverted from the environment and rambling, extroverted surface forms that open to light and air. Image also comes into the conversation. Would this design pres­ent a corporate image of a large and powerful institution, or would it be a human-scale village of office suites?

The new NMB complex would not only have to answer these internal questions, but would also have to provide its own service infrastructure. The existing park­ing and local amenities were insufficient to service the business of a large modern banking institution. Restaurants, shops, and other support services would have to be created.

Contextual

The ambitious scope of the program and its site on the fringe of Amsterdam’s mid-rise urban fabric suggest that the bank would have a strong impact on the community. More than an infill project, the complex of new buildings would be a centerpiece among the existing nondescript structures. A strong social statement would be unavoidable.

NMB was shaping up as a small self-contained city. Given the size of the banking complex and its location among neighborhoods where many of the NMB staff lived, important questions of context arose. How would the development fit into the gray mid-rise neighborhood? How could it elevate the urban environment it was to occupy? Finally, with Alberts & Van Huut’s organic expres­sionist ambitions, how would the resulting forms blend with the existing background structures?

Intentional

Alberts’s intention of creating a warm and friendly, yet progressive, environment meshed well with the bank’s desire to change its public image. But it created challenges as well. How could the scale of the large building program be broken down to a human level? How would organic form be compatible with program and technical require­ments? Further, how would the design balance societal and individual friendliness with the needs and organiza­tion of a large corporate client?

Appropriate Systems

Precedent

Although Alberts toured the Berlin Philharmonica with his client, and despite the visual resemblance of NMB to Antonio Gaudi’s organic ultrabaroque examples like Casa Batlo, the precedents for this project are elsewhere. As a formal model, Alberts turned to the origins of his natura­listic beliefs and based the design directly on Rudolph Steiner’s Goetheanum. There is a very close correspon­dence between the pentangle plan of the Goetheanum and

that of the typical NMB office plate.

Rudolph Steiner (1861-1925) studied at the Vienna Technical College, where he absorbed the philosophies of Goethe and Nietzche. He was the founder of Anthroposophism, a belief founded on the of knowledge of human nature and the central role of humanity in the cos­mos. Steiner later developed an architecture based on the alignment of science and nature. He produced few build­ings, but is recognized for his design of the Goetheanum in Basel, Switzerland, and the campus of structures that still make up the anthroposoph compound there. Connections to the Goetheanum are strengthened by the fact that Alberts and Van Huut were practicing anthroposophs, as was the chairman of NMB and much of his staff.

Site

A great deal of design effort was invested in capturing pri­vate garden space off the main circulation spine. This was achieved by developing terraces above the parking garages and on the roofs of ground-level retail shops. There were also two large terrace-level gardens captured as center­pieces between groups of towers. They are covered with different soil types appropriate to the variety of gardens maintained. The east office blocks wrap around the Japanese Garden and the west towers make a corner at the Winter Garden. Similar attention is given to the one-third of the site left as open space and devoted to public plazas surrounding the building.

The S-shaped internal corridor that connects all ten of the office blocks crosses over a small street off the main entrance facade from Hoogoorddreef Street. At this point the complex and its podium are divided into two halves. The five east side towers are connected 16.4 ft (5 m) above grade to the five west side towers by a three-level walkway bridging across the 65 ft (19.8 m) span. The walkway is an extension of the principal interior street and the intercon­nected stairways between the office blocks. Executive and employee entrances are located at the southwest corner of the complex. Parking for about 750 cars is buried within the large podium base.

Structure

From the ground up through the internal pedestrian street the building is supported on concrete columns. Vertical structure above the grand corridor level consists primari­ly of 7.1 in. (180 mm) precast concrete panel exterior walls. Internally, three continuous columns run up the open tower atriums to carry spans of the floor. The towers, elevator shafts, and fire stairs act as independent rigid structures. Floor spans are of 11.8 in. (300 mm) poured – in-place concrete slabs. They unite the vertical concrete panel boxes laterally into a stable structure.

A special condition occurs where the sloping exterior walls, with angles up to 14 degrees from vertical, produce a horizontal thrust at their base. The transition takes place at a point where loads change from uniformly distributed concrete panel walls above to point load columns below. This is nicely resolved by a forest of tapered and angled columns positioned below the load-bearing concrete pan­els and canting visibly through much of the public and open lobby space.

Envelope

The overall configuration of the complex is broken up to reduce its scale and to provide easy penetration of daylight. This strategy also aids the diffusion of noise and wind. Most exterior walls are fragmented, chamfered, and sloping. Two larger facades facing the main street are set at angles to deflect sound laterally rather than allow it to bounce back and forth in an urban noise canyon between buildings.

The bank’s exterior cladding consists of 600,000 cus­tom bricks in 59 different shapes and more t han 2 million standard bricks. Precast concrete lintels above the win­dows create horizontal banding patterns across all eleva­tions. These bands are accentuated by carrying their lines through the brick coursing.

Each of the ten towers is capped by a glass roof that covers its air-handling equipment and atrium. The mechanical penthouse scheme is similar to the one used at Briarcliff House by Arup Associates (see case study # 8). The feature element is a repeated 1400 ft2 (130 m2) sloped skylight in the form of a pentagram-shaped window. Most of these skylights manage to face generally into the south sun, but a few are oriented more to the north.

Insulated glass windows are punched through 25 per­cent of the brick facade in a regular pattern. Each opening is spanned by a structural precast concrete lintel. Typically, windows are divided into three panels or “lites.” The lower lites and the interior blinds are operable by office occu­pants. Metal louvers acting as small light shelves are locat­ed outside the upper transom lite. Shading of the two lower panels is handled by metal blinds suspended on the exterior of the window from below the top transom. These blinds are raised and lowered by automatic controls from a metal housing for the motor that also covers the blades of the sunshade until they are lowered.

Mechanical

Conservation at NMB begins with a total energy system. Two 450 kW generators are driven by engines that can run on either natural gas or fuel oil to produce electricity on­site. Typically, about 90 percent of the energy used by fuel – burning engines ends up as waste heat in the exhaust flue and only 10 percent is delivered as usable horsepower. But the waste heat can be recovered by cooling the engines with circulating water and then storing it in large hot water tanks. In Amsterdam’s cool climate, there are plenty of opportunities to recycle the “total” energy consumed by the engines.

Thermal storage of waste heat is held in four 6,605 gal (25,000 l) water tanks of heavily insulated concrete buried beneath the main thermal plant. The 26,420 total gallons of water are charged primarily by cooling the generator engines, but also by recycling heat rejected from air-con­ditioning chillers and even elevator motors. Hydronic radiators located along the perimeter of the office spaces warm the rooms with hot water circulated from the stor­age tanks. Backup heating is provided by a 1000 kWh gas – fired boiler but is required only during repairs to the main system and in extremely cold weather.

Two 206 ton (730 kW) absorption cooling systems convert the high-temperature waste heat from cogenera­tion engines into cooling energy for summer days and for computer rooms. A conventional electrically driven 267 ton (940 kW) chiller provides emergency backup. Under Holland’s 1980s building code, conventional cooling equipment could be provided only if it was required to offset heat gain from equipment loads.

Ceramic heat wheels are used to recover heat from exhaust air and simultaneously preheat incoming venti­lation makeup air. Such systems usually save 90 percent of the energy normally lost to ventilation during cold weather. Vertical distribution of ventilation air is han­dled in each tower by a continuous chase at the center of the floor plate aligned against one narrow edge of the atrium.

Primary energy consumption for the office complex is 28,031 Btu/ft2 (96 kWh/m2). Another 4,380 Btu/ft2 (15 kWh/m2) is used by retail and residential buildings located across the plaza. The Dutch Research Establishment certi­fied total NMB energy consumption levels at 32,411 Btu/ft2 per year (111 kW/m2 or 400 MJ/m2). This is more than 90 percent below that of the bank’s previous headquarters and slightly less than the 33,287 Btu/ft2 (114kW/m2) annual consumption of the previous record holder for energy effi­ciency, the Obayashi Gumi building in Japan.

Interior

The organizing principle of the individually small office floors is based on the bank’s operational program. It pro­vides for five work groups per floor. Each group includes a team of 8 to 10 people, so there are approximately 40 or 50 occupants on each typical office floor.

Figure 11.17 Interior view. (Photograph courtesy of Gary J. Coates.)

The marble floor pedestrian street is the connecting element of the complex. The winding pathway is filled with artworks designed for their special place in the
building. Light sculptures and stained glass windows acti­vate the penetration of light through the glass-roofed atrium at each office tower. Water runs through the space in “flow-form” sculptures and pools of collected rainwa­ter for the interior plantscaping. Even the stair handrails are used as small streams and fountains. Plants are locat­ed in the public spaces to regulate humidity and cleanse the air. The greenery is part of the rainwater filtration system that cascades through the interior of the building. Open stairways are given more visual presence than ele­vators as an invitation to walk through the space rather than ride up and down. There are only 21 elevators in the entire complex.

Natural materials are used wherever hands touch the building and wherever finish surfaces are needed. Suspended ceilings, for example, are made of wood slats. Textured paints of different colors are used on concrete surfaces to give a sense of individual identity in each office tower. The shades of color are subtly varied according to exposure: cool tints for the sunny sides and warmer tints in shade.