v24_RUPNIK

Prefab City A compendium of strategies for prefabricated building techniques in urban environments

Site Access There are several logical reasons for using cranes in prefab construction. Sites completely surrounded are rendered inaccessible to bulky construction equiptment.Other existing site conditions like single access to site, corner site, or narrow site greatly limit the access points to bring in construction equiptment and modules.

Buildings can be constructed on these accessible (but difficult) sites and open sites using stick frame methods, but in some cases the speed of prefabricated construction methods can expedite the process.

courtyard

crane necessary for construction

surrounded site

single access to site

INTRODUCTION DETERMINANTS

corner site

narrow site

full access to site

Site Access + Assembly • 28

PRECEDENTS

CONTEXT

crane necessary for speed

DEPLOYMENT

alley

Crane Operation + Extents Special crane components There are some extra equiptment items that make craning a module more efficient and precise.

Rigging keeps the forces of tension perpindicular to the module, reducing the bending forces on the unit. An antirotation device helps control a crane’s motion and the way the module shifts from pickup Winch up

Winch left

to placement.

Winch right Winch down

Emergency stop Start

Stop

Jog

Reset

Wood frame modules are best moved with strapping and rigging. Steel frame modules use

Crane school

hooks and holes intentionally in the design of

Heavy equiptment training school is essential for

modular structures to pick up the unit (as in

crane training and operation. It involves written

shipping containers).

tests based on state laws and practical examinations employing students’ skilled

Outriggers extending from the crane vehicle are

manipulation of the crane operations.

necessary to temporarily ground the module to the site.

The jib is very useful to hold the modular unit in an almost upright position. It has the potential to resolve design issues thanks to its ability to

Crane cab controls

suspend the module in a way different from the way a crane typically does.

Rigging for wood frame module

INTRODUCTION

Small And Large Crane Extents All Terrain Crane Tadano ATF 110G-5 130 Ton capacity

jib

20°

20°

DETERMINANTS

143' 80° jib 122' 44°

95' 20°

80° 42'

170'

CONTEXT

101' 130'

PRECEDENTS

360° work area

outrigger

72'

24'-7"

340'-0"

outrigger

20'-0"

190'-0"

56'

DEPLOYMENT

Telescopic Boom Crane National Crane 1395 20 Ton capacity

360° work area

Site Access + Assembly • 30

Crane + Obstacles Hand signals

Permitting obstacles

between the crane operator and the individual on

Inspectational Services Department include: long

site guiding the placement of the crane. These

form permit, amendment, use of premise permit

simple gestures are necessary for several

(for using open space), electrical & fire alarm

reasons. Construction sites are often loud. There

permits, plumbing, gas, and sprinkler installation

is a lot of space between the crane operator and

permits.

Hand signals are necessary for communication

Permits in Boston one must obtain through the

the individual conducting the crane’s motions.

The dual perspectives of crane operator and

Call Boston Public Works Department 24 hours

conductor are critical in ensuring safety and

prior to work to get a permit. Coordinate with

precision.

recycling, santiation, and street sweeping. Signs must be posted near the sitewith the construction schedule. In addition to this, it may be required to hire an officer to direct traffic.

Hoist

Swing

Lower

Raise Boom + Lower Load

Raise Boom

Lower Boom + Raise Load

Lower Boom

Stop

Hand signals

INTRODUCTION

Obstacles on a construction site There are a variety of existing physical barriers

that must be worked around. These can lead to interesting, even fruitful design moves. They includew but are not limited to:

DETERMINANTS

Utility poles Power lines Lamp posts Trees Fire hyrdants

PRECEDENTS

CONTEXT

DEPLOYMENT

Subterranian utilities

Site Access + Assembly • 32

Off Frame Assembly Site Dimensions Determined by Truck Turn Truck turn dimensions can influence the decision to use a site or not. Sometimes scale and cost can dictate the use of an off frame assembly system. Often obstacles, like powerlines, can make modular construction on a site unfeasible without the use of an off frame solution. Still other obstacles, like sidewalks and buildings surrounding the site (both immediately and across

20' 6' 52' 6'

the street), can impact the delivery of an off frame modular unit.

Knowing the limits and minimum site dimensions can transform a once unusable site into a valuable piece of real estate.

Standard Semi Truck

Efficiency

minimum site dimensions 20’ wide x 53’ deep module dimensions 8’-6” wide x 53’ deep

Efficiency percentage is calculated by dividing the area of the module by the area of the smallest possible rectangular site. It is clear that the most dense and efficient module-site relationship happens when the module is shorter and wider, as in the case of the oversized load (width) example.

Module

Site

43 %

INTRODUCTION 25'

6'

6'

6'

53'

53'

53'

6'

6'

6'

Stretch Semi Truck

Oversized Load (Width)

Oversized Load (Length)

minimum site dimensions 25’ wide x 48’ deep module dimensions 16’ wide x 48’ deep

minimum site dimensions 17’ wide x 63’ deep module dimensions 16’ wide x 48’ deep

21 %

64 %

50 %

Site Access + Assembly • 34

PRECEDENTS

CONTEXT

minimum site dimensions 41’ wide x 80’ deep module dimensions 8’-6” wide x 80’ deep

DETERMINANTS

17'

DEPLOYMENT

41'

Off Frame Assembly From Truck to Site

Off-Frame Modular Delivery Module delivery is possible without a crane. The truck begins its delivery by backing into the site.

Next jacks are placed underneath the module, taking the load off of the transportation chassis.

The chassis is then removed by pulling it out into the street. In some cases, like the illustrated scenario, a chassis must be cut into pieces because the distance between the in place module and existing structure across from the site does not allow its removal.

Backing up

Entering site

INTRODUCTION DETERMINANTS DEPLOYMENT CONTEXT

Removing chassis from site

Breaking up chassis

Site Access + Assembly • 36

PRECEDENTS

Placing jacks under module