Perbedaan struktur P.3 sendi dan struktur Cangkang
378 Arch, Suspension. and Shell Systems
FIGURE 11-1
THE MOMENT-RESISTING FORCES IN AN ARCH OR SUSPENSION
SYSTEM ARE LOWER AS COMPARED WITH A BEAM SYSTEM
BECAUSE THE OVERAll DEPTH (h) IS GREATER.
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I
N~CN SI4APL GIVEN BY MOMENT
DIAGRAM
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$IJSPLNSION S~AP~ 6IVEFJ
MOMCNY OIAGtAil
P~K)TE TI-tAT TF4C IPLAL’ SNAPC-
FOR PJ’J ARCH OR OUSP~NSION
SYSTuI IS ~~_uIVILCNT TO TI-IC DESIGN LOAD t~M[hJ1 OiPC.RAM
surfaces are desired, an auxiliary flat system must be supported or suspended
from a primary curved structural system.
In this chapter we will discuss three types of curved systems: (1) arch
systems, (2) suspension systems, and (3) shell systems. Shell systems will be
discussed last because they employ many of the principles that will be
discussed for arch and suspension systems, and they take many different
shapes. Thus Sections 4 through 7 will deal separately with folded-plate,
cylindrical, dome, dish, and hyperbolic parabaloid shells.
SECTION 2: Arch Systems
Since the beginning of history, mankind has tried to span distances using arch
construction. Essentially this was because an arch required materials resisting
only compression, and large quantities of materials like stone or mud for bricks
were readily available. Later, fired brick, concrete, and steel were produced and
utilized.
The basic issues of statics in arch design are illustrated in Figure 11-2. A
uniform load, (w) units per linear foot, is supplied along the projected horizontal
length of the arch. Due to symmetry, the vertical component of the end reactions
is V = wLI2 (Figure 11-2a). Note that this load reaction is
Model Struktur Cangkang
lCubah
Schwtdler
Kubab betrib
Kubah
geodesik