Our Visit from IBA HAMBURG, Introduction and Purpose of this Innovative Building

IBA DOCK: A Hub of Innovation and Inspiration in Hamburg

Introduction:

The IBA DOCK not only houses the exhibition of the International Building Exhibition 2006-2013, but is also itself an exhibit of  innovative building and energy-saving technologies: the building is situated on an approximately 50-metre-long and 26-metre-wide concrete pontoon; the superstructures are made of steel in modular construction. This saves weight and makes it possible to remove a part of the superstructures in case of transport, so that the IBA DOCK can also navigate under low bridges. The IBA DOCK was designed by the Han Slawik Architectural Bureau in Hannover; the 10-month construction period was coordinated by the municipal development company ReGe Hamburg Projektrealisierungsgesellschaft (Project Realisation Company) mbH.

What is the purpose of the IBA HAMBURG?

1. A Center of Inspiration: IBA DOCK is a place where architects, urban planners, researchers, and enthusiasts come together to share knowledge and inspiration. The dynamic atmosphere encourages dialogue, fostering the exchange of ideas that push the boundaries of architectural and urban design. Whether through exhibitions, workshops, or conferences, IBA DOCK sparks creativity and fuels innovation.

2. Architectural Exhibitions: The exhibition spaces at IBA DOCK showcase an impressive collection of architectural projects, highlighting the latest trends and advancements in the field. From scale models to digital presentations, these displays immerse visitors in a world of visionary designs. Here, today on 08, June 2023 we witness the evolution of urban landscapes, explore sustainable building techniques, and discover groundbreaking concepts that redefine our perception of cities.

3. Collaborative Workshops: IBA DOCK is not just a passive showcase; it actively engages visitors through interactive workshops and design charrettes. These collaborative sessions bring together architects, designers, and urban planners to tackle real-world challenges, brainstorm ideas, and propose innovative solutions. The workshops at IBA DOCK foster interdisciplinary collaboration, nurturing a spirit of cooperation and creativity.

4. Future-oriented Conferences: At IBA DOCK, thought-provoking conferences and symposiums take place, exploring the future of urban development and architectural trends. Experts from around the world gather to share their insights, research, and experiences, shaping the discourse on sustainable cities. These conferences inspire attendees to think critically and envision a more inclusive, environmentally friendly, and socially vibrant urban future.

5. Networking and Idea Exchange: IBA DOCK is a melting pot of ideas, where professionals and enthusiasts can network, forge connections, and find potential collaborators. From casual conversations over a cup of coffee to structured networking events, IBA DOCK cultivates an environment that fosters meaningful connections. These interactions often lead to innovative partnerships, further fueling the advancement of architectural and urban design.

Conclusion: IBA DOCK embodies the spirit of exploration, innovation, and collaboration that drives the architectural and urban design community in Hamburg. With its dynamic exhibitions, interactive workshops, inspiring conferences, and vibrant networking opportunities, IBA DOCK serves as a catalyst for change and progress. By bringing together visionaries and enthusiasts, it fosters a shared vision of sustainable, livable, and aesthetically pleasing urban spaces. Whether you're an architect, a student, or simply someone passionate about the future of cities, a visit to IBA DOCK promises to ignite your imagination and leave you inspired.

at last but not least, On behalf of all my classmates I am really thankful of ELBCAMPUS Management and Organizers especially Mr. Heornicke, Mr. Dolgij and Mrs Gesa von Maydell for such an Interesting class and site visits.

Naeem Nekmal

09, June 2023

Hamburg, Germany

How to Calculate Steel Quantity for Slab, Footing, and Column?

Estimation of steel reinforcement quantity for concrete slab, footing, and column, beams, etc. is crucial for the cost evaluation for the construction. Design drawings are used as a base for computing rebar quantity in different structural elements.

This article presents the steel quantity computation process for slabs, columns, and footings.

Calculate Steel Quantity for Slab

Obtain slab dimension and reinforcement details from design drawings as shown in Fig.1.
Compute the number of steel bars.

Main Steel Bars

No. of bars= (Slab length(L)/spacing)+1 Equation 1

Shrinkage and Temperature Steel Bars

No. of bars= (Slab length(S)/spacing)+1 Equation 2

In equation 1, the center to center spacing of main reinforcement steel bars are used and shrinkage and temperature bar spacing is used in equation 2.


Fig. 1: Types and arrangement of steel bars in one way slab

3. Calculate cutting length:

Main steel bars

Cutting length= clear span(S)+Ld+inclined length+2×45 degree bend Equation 3

Shrinkage and Temperature steel bars

Cutting length= clear span(S)+Ld+inclined length+2×45 degree bend Equation 4

Where:

Ld: development length which illustrated in Fig. 2.

Inclined length can found from the following expression:

Inclined length= 0.45D Equation 5


D=slab thickness-2*concrete cover-bar diameter Equation 6


Fig. 2: Bent up bars in slab

• 3. Convert that length into kilograms or tons because steel bars are ordered by weight. The same equation used for both main and shrinkage and temperature reinforcement, but corresponding cutting length, number of bars, and bar diameter is used.

Main steel bars=No. of bars*cutting length*weight of the bar (/162) Equation 7

(/162) is the weight of steel which is derived from steel volume times its density which is 7850 kg/m3.

Calculate Steel for Footing

The size of the footing and its reinforcement details (bar size and spacing) shall be known. This can be achieved from design drawings. After that, the following steps will be taken to compute the steel quantity.

• calculate the required number of bars for both directions.

No. of bars = {(L or w – concrete cover for both sides) ÷ spacing} +1 Equation 8

where L or W: length or width of the footing

• Then, find the length of one bar

Length of bar = L or W–concrete cover for both sides + 2*bend length Equation 9

Where L or W is length or width of the footing

• After that, compute the total length of bars which is equal to the number of required bars multiply by the length of one bar. If the same size of bars is used in both directions then you can sum up both the quantity of the bars
• Convert that length into kilograms or Tons. This can be done by multiplying cross-section area of steel by its total length by the density of steel which 7850 kg/m3

The above calculation procedure is for a single reinforcing net. Therefore, for footings with the double reinforcing net, the same procedure need to be used again to compute steel quantity for another reinforcing net.

Calculate Steel Quantity for Columns

Achieve column size and reinforcement detailing from design drawings. Then, compute the quantity of steel in the column using the following steps:

Longitudinal steels

1. Compute the total length of longitudinal bars which equal to the column height plus laps for footing multiply number of longitudinal bars.
2. Convert that length into kilograms or Tons. This can be done by multiplying cross-section area of steel by its total length by the density of steel which 7850 kg/m3

Stirrups

• Compute the cutting length of stirrups using the following equation

Cutting length=2*((w-cover)+(h-cover))+Ld Equation 10

where:

w: column width

h: column depth

Ld: stirrup development length

• Calculate the number of stirrup by dividing column height over stirrup spacing plus one.

• Estimate the total length of stirrup which is equal to stirrup cutting length times number of stirrups.

• Convert that length into kilograms or Tons. This can be done by multiplying the cross-section area of steel by its total length by the density of steel which 7850 kg/m3.

Total steel quantity of columns equal to the sum of both main and stirrup steels.

Rat Trap Bond – Construction, Advantages, and Disadvantages

Rat trap bond is a modular type of masonry bond in which the bricks are placed in a vertical position which creates a cavity in the wall while maintaining the same wall thickness as that of the conventional brick masonry wall. It is also known as a Chinese brick bond.

The purpose of using this type of masonry bond is to reduce the number of bricks and mortar required as compared to the English/Flemish bond because of the cavity formed in the wall.

Fig 1: Rat Trap Masonry.

Architect Laurie Baker introduced it in Kerala in the 1970s and used it extensively for its lower construction cost, reduced material requirement and better thermal efficiency than conventional masonry wall, without compromising the strength of the wall.

In this article, we discuss the material criteria, construction, advantages, and disadvantages of rat trap bond masonry.
Selection of Bricks

The criteria that are set for the selection of bricks is of utmost importance as less number of bricks are used in the construction of rat trap masonry.

The size of the bricks used must be of a standard size and variation in size is not accepted. The acceptable sizes of brick in Indian scenarios are – Length 220-250 mm, Width 100-115mm and Height 65- 75mm.
The edges and corners of the bricks must be straight and sharp and perfectly rectangular in size.
Having a uniform size of bricks is important as the masonry is the modular type and to achieve good strength and finish.

Table 1: The material strength requirement Rat Trap Bond


Type of Construction

Recommended Compressive Strength of Bricks Best Practice Minimum Allowable

Recommended Mortar Ratio


Load bearing, Double storied


40 – 50 kg/cm2

1:5

Load bearing, Single storied

35 – 40 kg/ cm2

1:4


Infill masonry in frame structure,
no restriction on number of floors

Min 35 kg/ cm2

Not less than 1:4

Construction of Rat Trap Bond
The bricks are placed in a vertical position so that 110 mm face is seen from front elevation, instead of the 75mm face (considering brick of standard size 230 X 110 X 75 mm).
As the width of the wall is kept as 230mm, a cavity is created inside the wall.
However, the first and the last layer of the masonry is constructed as the convention sold masonry.
In the sill, lintel and sides of openings are made of solid masonry (without cavity) for fixing of frames.
To strengthen the masonry, vertical and horizontal reinforcement bars are provided in the cavities.
Electrical conduits and plumbing pipes, with prior planning, can be put inside the cavity for better aesthetics.

Fig 2: Construction of Rat Trap Bond

Image Courtesy: ArchitectureLive!
Advantages of Rat Trap Bond
The cavities in the masonry act as thermal insulators. Thus, the interiors remain cooler in summer and warmer in winter.
Rat Trap masonry uses fewer bricks and mortar reducing the cost of masonry up to 30% when compared with conventional brick masonry.
The number of bricks used in the construction of rat trap masonry is 470, whereas, in conventional masonry, it is 550.
Walls constructed using rat trap masonry can be used as load-bearing as well as a thick partition wall.
Rat-trap bond when kept exposed, creates aesthetically pleasing wall surface and the cost of plastering and painting may also be avoided.
As this type of masonry has 30% of cavities, the dead load of the structure is reduced which in turn reduces the structure supporting members such as column and footing.
In case of more structural safety, reinforcement bars can be inserted through the cavity until the foundation.
Many buildings that were constructed decades ago have proved that this type of walling technology is durable and the maintenance costs are low.
Disadvantages of Rat Trap Bond
Due to the formation of cavities in the masonry, the building does not provide good sound insulations.
Skilled labor is required to construct this type of masonry.
Frequent cleaning of external surface required if not plastered.
Special care and attention to be given while designing and constructing rat trap bond masonry.

Pre-Cast Concrete Walls – Types, Connections, and Advantages

Precast concrete walls are constructed by casting concrete in a reusable wall mold or form which is then cured in a controlled environment, transported to the construction site and lifted into place. The main function of the precast walls is to speed up the construction process.

Fig 1: Erection of Precast Concrete Wall.

In this article, we discuss about the types, connections, characteristics, and advantages of precast concrete walls.
Types of Precast Concrete Wall

1. Cladding or Curtain Walls
The cladding or curtain walls are the most widely used precast wall for building envelopes. They are non-load bearing walls intended for the use to oppose the wind and encase the space. This type of precast wall incorporates divider boards, window divider units, spandrels, mullions, and section covers.

2. Load-bearing Wall
Load-bearing wall units oppose and exchange loads from different components and cannot be removed or dismantled without influencing the quality or dependability of the building.

Fig 2: Load Bearing Pre-Cast Concrete Walls

3. Shear Walls
Shear walls are utilized to give a parallel load opposing framework when joined with stomach activity of the floor development. The viability of precast shear dividers is generally needy upon the board-to-board associations.

Types of Connections in Precast Concrete Walls

1. Bolted Connections
The bolted connections are a simplified and fastest method of erection operation. The final alignment and adjustment can be made later without tying up crane time. The bolting should be in accordance with the erection drawings, using material specified by the designer.

2. Welded connections are the most common and typical connection used in the erection of precast concrete. These connections are structurally efficient and adjust easily to varying field conditions.
The connections are usually made by placing a loose plate between two structural steel plates that are embedded both in the cast-in-place or the precast concrete panel and welded together.

3. Dowel/Anchor Bolt Connections 
In a dowel connection, the strength of dowels in tension or shear depends on dowel diameter, embedded length, and the bond developed. The threaded anchor bolts and rebar anchor dowels that protrude from the foundation are the critical first connection to precast members.

Structural Design Aspects
The precast walls are designed as blind divider or facade which does not carry any load. Anyhow, the precast walls must oppose parallel loads conferred on it due to self-weight, winds, and quakes.

It is critical to assess the plan, specifying and erection of precast walls to abstain from forcing undesirable burdens onto the walls. Loads such as erection, affect, and development related, and transportation of the precast walls are to be considered in the design phase.

The joints between the walls must be sufficiently wide to suit warm extension and differential developments due to season variations. The divider hole space and go down divider which is secured with a water-safe film give an optional line of assurance against water infiltration into the building.
Characteristics of Precast Concrete Walls

1. Thermal Resistance
The precast walls infer their warm execution attributes basically from the measure of protection set in the depression or inside the reinforcement divider, which is ordinarily a metal stud divider.

2. Moisture Protection
The protection for the moisture in the precast walls is of high importance as the structural members such as columns and beams are not structurally connected with the precast walls.

The sealer or the joint seal used in the connections and joints to prevent the moisture from entering the building. To keep the uniformity of precast walls and the sealants, pigmented sealants are used.

3. Fire Safety
The precast walls are manufactured with concrete which has good fire-resistant material.

3. Acoustics
A precast wall with a veneer will give comparative execution with respect to sound transmission from the outside to the inside of the building.

4. Durability
The durability parameter of the precast walls is the same as that of concrete. Anyhow, the durability depends on the type of connections made with the structural member.

Any irregularities in the member can be rectified by sandblasting, uncovering total, corrosive washing, hedge pounding, or different methods.

5. Maintainability
As the walls are manufactured with concrete, which does not need any maintenance. The connection, sealants, anchorages, and accessories used in the precast walls need regular maintenance.

Fig 3: Pre-Cast Concrete Wall

Advantages of Precast Concrete Walls

Precast concrete walls act as thermal storage to delay and reduce peak thermal loads.
The precast concrete wall is used as an interior surface which saves time and money by eliminating the need for separate stud framing and drywall costs.
The precast concrete wall can be used as load-bearing structures and will save costs by eliminating the need for an additional structural framing system.
Precast concrete walls can be designed to be reused for future building expansions.
Precast concrete’s durability creates a low maintenance structure, which stands up to harsh climate conditions.
Precast concrete colors and finishes can be achieved through the use of various aggregates, cement, pigments and finishing techniques.
Precast concrete wall panels can utilize a thin brick veneer that can achieve a traditional appearing facade.
Precast concrete walls can be produced with textures including form liner shapes, artwork, and lettering to provide distinctive accent treatments.
Precast concrete wall panels can have electrical boxes and conduit cast into the panels, to provide flush electrical fixtures on walls that are not to be framed out.