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Timber in the City: Glulam Forest

June 7, 2013 Leave a comment

silei_extrender

Above: exterior render image of the digital fabrication block

silei_site_diag

silei_massing

The project departed from the concentric city plan of Mandalay, acting as an urban intervention that reflects the grid layout. The workshop and residential blocks are linked via an elevated walkway on the second level.

silei_kielsteg

dint

wfacade

The wood and digital fabrication blocks are differentiated through the language of the columns – rectilinear for the wood production block and curved for the digital fabrication block – in order to reflect the processes taking place in the workshop. The roof uses Kielsteg as a long-span solution.

silei_digisim

silei_prodsim

Simulations were done using Autodesk Simulation Mechanical 360 in order to check the feasibility of the shape of the columns as well as to find the optimum column grid.

prodfinalproto

silei_digiproto

Prototypes of the columns were also made in order to better understand the nature of timber as a construction material.

Categories: AY 2012/2013 SEM 2

Studio field trip to Myanmar, 21-27.02.2013

May 29, 2013 Leave a comment

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Categories: AY 2012/2013 SEM 2

Cloud V

May 24, 2013 Leave a comment

overall render

Inspired by the same structural principles as the Dougong Cloud project, Cloud V is the vertical variation of the DouGong (bracket and block) timber joinery system. Designed as a hybrid timber (beams, columns) and concrete (floor slabs, cores) high-rise service apartment block in Mandalay (Myanmar), considerations were given mainly to structural tectonics and integrating with on-site climatic conditions.

Structural Tectonics

structural components1

Like a DouGong column head, the main structural strategy is to support a large volume of space using a small footprint. Forces would be distributed downwards from a larger congregation of members to a smaller assembly of members connected perpendicularly to one another in layers. Through the massing phase, the 3 blocks are angled to reduce accumulated solar radiation from the South and East sun, while maximising daylight entry for each room. This creates a large scale cantilevered structure, similar to how a DouGong is assembled. To manifest the fore-mentioned idea, the overall structure was inspired by the construction of a Japanese Pagoda, which employs 2 main structural principles:

1) The central structural member is non load-bearing.

sper
Vertical and Horizontal forces are transferred strictly from beam to column without depending on the central column, or in this case, the core. Thus, the central core is freed up from its load bearing functions. This is expressed by the skylight void around the core to emphasize the departure of the vertical core as a recognised strong load-bearing element. Thus, the core is used for vertical circulation and housing M&E services. Moreover, in terms of climatic considerations, daylighting is able to be achieved for the lower floors. Light is able to enter from the top and is channelled down to the first few storeys.

 

2) Staggered Column Grid

plan
To avoid the concentration of forces on vertical members, a staggered column grid is generated to allow distribution of load-bearing forces. As such, no single column takes the accumulated load of more than one floor plate and this reduces the amount of material invested in each column. Furthermore, this arrangement of columns allows natural ventilation to occur as wind can be channeled through along the East-West axis between the rooms.

Visualisation of Structural Components

Due to the cantilevered structure, stress will be concentrated on areas where the column meets the beam. This is resolved by identifying and strengthening these areas with more timber members, done with Scan&Solve along with Grasshopper’s image sampling. Thus, the structural framework is built by adding members to the existing column-beam system, allowing weaker wood pieces to gain strength through the layering process.

simulations

Model

A von Mises simulation is run on the whole building frame (slabs and columns only) and the B/W stress images of each floor plate is used. Next, beams and transfer beams are then added to reduce the displacement of the floor plate. However, this does not resolve the amount of stress on each column and at the intersections where column and beam meet. Thus, a DouGong column head is layered at the top of every column. As from the results, both stress and displacement values are greatly reduced from the columns and floor slabs. This form of structural assembly is then generated for the subsequent floors.

The construction assembly is via a stacking system where the composite concrete-CLT floor plates are cast in place, followed by the addition of the timber columns and then, the addition of the window frames and railings. Timber Beams are added and capped by modular ceiling panels. Next, the timber column head DouGong is fitted in place with the timber transfer beams at the top to hold the load for the next floor slab.

yy_section perspectiveSectional Perspective of Structural Assembly


intren1Rendering of Rooptop Terrace

interior3Rendering of Ground Floor lobby and Bicycle Shop

Categories: AY 2012/2013 SEM 2

Dougong Cloud

May 22, 2013 2 comments

Digital Fabrication Perspective

Design studio project by James LAU

 

The Problem

Timber has always been difficult to specify – only specifying the cross-section is relatively flexible. Due to natural occurrences of undesirable defects (shakes, wind cracks, upsets, etc.), there is a large amount of waste generated from sawn timber not being able to meet the required specifications. The longer the timber required, the higher the chances of waste being generated. This design exploration seeks to tackle this problem and re-introduce timber architecture aesthetics.

 

The Idea

This is a digital fabrication factory that takes inspiration from the traditional 斗拱 “dougong” construction system commonly found in traditional Chinese or Japanese architecture, especially pagodas. This modern interpretation of the system gives use the ability to utilise small standard cross sections available in the local market of the site and create large spans of approximately 35m. By joining the smaller timber components lengthwise using traditional Japanese timber joinery such as the 継手 “tsugite”, usable yields from sawn timber has increased. In addition, the new lengths of timber performs almost as if it was one solid timber sawn from a log.

With the porosity of the roof structure that the dougong system provides, there is the opportunity to bring in daylighting and reduce electrical lighting reliance during the working hours of the factory.

Exhibition Perspective

The Design

The Dougong Cloud is a long span space where the columns can be freely placed according to the programme of the space and the required span. Through the initial placement of the columns, the span is that calculated from column to column and column to building edge boundary. With the acquired spanning requirements, layers of dougong will be added based on the span and structural performance.

Dougong Cloud Concept

The following is a cropped elevation as seen from the exhibition building.

Dougong Cloud Partial Elevation

There is a visible play of varying number of layers and position of columns. It was a conscious design decision to retain the columns instead of using the dougong system to replace the column so as not to waste material through excessive use. In this case, the vertical element of the column would suffice. It is almost as if the column head itself morphs into the roof.


Section Detail of Digital Fabrication Factory

Section Detail of Digital Fabrication Factory


Section Perspective of Digital Fabrication Factory

Section Perspective of Digital Fabrication Factory


Exploded Axonometric

Exploded Axonometric

The Process

The following is a diagram of the exploration beginning with the traditional column, beam construction concept. It is then replaced with the standard timber sections and tested using Autodesk Simulation 360 to understand its performance.

Dougong Exploration

Roof layers: 6
Dougong Layers: 8
Step size: 1500

2000-l6-dg8-1000-1500_d_front copy


2000-l6-dg8-1000-1500_vM_front copy

Roof layers: 6
Dougong Layers: 6
Step size: 2000

2000-l6-dg6-1000-2000_d_front copy


2000-l6-dg6-1000-2000_vM_front copy

Roof layers: 6
Dougong Layers: 5
Step size: 2500

25000-l6-dg5-1000-2500_d_front copy


25000-l6-dg5-1000-2500_vM_front copy

There were three basic column configuration to test the structural properties of this system when being used for the following programme respectively: digital fabrication factory, traditional timber factory and exhibition hall.

Overall Plan

Each building is then modelled in Rhino and Grasshopper. Subsequently, simulations are then executed with the same 3D model, followed by fabrication.



Grasshopper File

Grasshopper File


Digital Fabrication Factory

Building Plan

Plan of Digital Fabrication Building


DIVA Simulation in Grasshopper

DIVA Simulation for Digital Fabrication Building

The lux levels in the building is simulated using the weather file for the site and the average was taken across the year in an overcast condition. Within the space, the average lowest lux levels was found to be approximately 1200 lux. This proves that during the operation hours when daylight is available, for the tasks in this space, daylighting itself is more than sufficient.



Autodesk Simulation Mechanical 360

Displacement [Isometric, Front, Right]

Digital Fabrication Displacement [Isometric]


Digital Fabrication Displacement [Front]


Digital Fabrication Displacement [Right]

Most of the displacement occur as the beam spans away from the column, where the further it spans, the greater the displacement. However, the maximum displacement that occurred in the direction of the 35m span is within the threshold of 30mm.



von Mises [Isometric, Front, Right]

Digital Fabrication von Mises [Isometric]


Digital Fabrication von Mises [Front]


Digital Fabrication von Mises [Right]

Most of the stresses occur in the column and in the furthest cantilevered parts of the structure. The maximum stress still falls well within the mechanical properties of teak.



Traditional Timber Factory

Building Plan

Plan of Traditional Timber Factory


DIVA Simulation in Grasshopper

DIVA Simulation for Traditional Timber Factory


Autodesk Simulation Mechanical 360

Displacement [Isometric, Front, Right]

Traditional Timber Factory Displacement [Isometric]


Traditional Timber Factory Displacement [Front]


Traditional Timber Factory Displacement [Right]


von Mises [Isometric, Front, Right]

Traditional Timber Factory von Mises [Isometric]


Traditional Timber Factory von Mises [Front]


Traditional Timber Factory von Mises [Right]


Exhibition Hall

Building Plan

Plan of Exhibition Hall


Autodesk Simulation Mechanical 360

Displacement [Isometric, Front, Right]

Exhibition Hall Displacement [Isometric]


Exhibition Hall Displacement [Front]


Exhibition Hall Displacement [Right]


von Mises [Isometric, Front, Right]

Exhibition Hall von Mises [Isometric]


Exhibition Hall von Mises [Front]


Exhibition Hall von Mises [Right]