High Performance - Precast Concrete, Steel-Braced, Hybrid Pipe Rack Structures

Oct 24, 2026

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High performance design and construction of a precast reinforced-concrete pipe rack with steel bracing is presented through a case study at an operating petroleum refinery in Argentina’s high seismic zone. The structure uses precast reinforced concrete moment frames with a single cast-in-place connection, precast beams as shear keys, and steel V-bracing for longitudinal resistance. Connection details meet Argentine seismic requirements while reducing on-site concrete work and working-at-heights risks, and the paper addresses seismic demand, thermal anchorage forces, and construction acceleration considerations.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages13

Reading Time33 min

AccessFree to download

Project characteristics

Structure configuration

Seismic parameters and design spectrum

Boundary conditions and safety considerations

Minimizing cast-in-place concrete

Maintenance and operational requirements

Foundation system

Guidelines for operating petrochemical sites

Tie beams and differential settlement control

High Performance Precast concrete, steel-braced, hybrid pipe rack structures Sebastián F. Vaquero, Damián R . Correa, and Sergio F. Wolkomirski The construction of a precast, reinforced concrete pipe rack supporting process pipelines has many boundary conditions to be considered in design and construction. The most important ones are the following: ■ This paper presents a case study of the design and construction of a pipe rack in an operating petroleum refinery located ina high seismic zone in Argentina. ■ The pipe rack comprises precast, reinforced concrete moment frames with a single cast-in-place connection as the transverse load-resisting system, longitudinal precast, reinforced concrete beams as shear keys, and steel bracing as the longitudinal load-resisting system. ■ The connections comply with the requirements of the Argentine seismic code, taking into account the erection tolerances and minimizing on-site concrete work as well as working at heights. • The strict safety guidelines of petrochemical facilities discourage the use of cast-in-place concrete. Normally all maintenance, repair, and construction work must be conducted with a proper work permit, which can be difficult to get. The permit is a detailed document that authorizes certain people to conduct specific work ata specific site at a specific time and sets out the main precautions needed to complete the job safely. Precast concrete systems help minimize such problems. • In the petrochemical industry, delays are costly. • Flare gas pipelines are gravity fed because their condensate is extremely corrosive. Unlike other process lines, they cannot be placed on the ground with slider bearings. In the operation of an oil refinery, flare stacks are primarily used for burning off flammable gas released by pressure relief valves during unplanned overpressurizing of plant equipment. Gas-gathering pipelines are required to transport flammable gases to the flare stack to provide a means PCI Journal | Fall 2013 55 High Performance Figure 1. Project characteristics. Note: 1 m = 3.28 ft, 1 mm = 0.0394 in. of safe disposal of the vapor streams from the facility by burning them under controlled conditions so that adjacent equipment or personnel are not exposed to hazards while atthe same time obeying environmental regulations. Thermal variations due to the content of the pipes or ambient temperature differentials result in significant anchor forces. The pipe rack is intended to resist, or limit, the movement of the piping because equipment connections, such as the ones available in vessels or tanks, are not generally designed to handle the resultant thermal forces. The specific project characteristics were as follows: • The process pipelines are supported on precast concrete cantilever columns along a 300 m (1000 ft) path. • The piping is anchored to the frame at the end of the path, resulting in significant horizontal thermal loads (about 60 kN [13.5 kip]) . • The structure’s height is 11 m (37 ft) due to process requirements. • The main pipes have external diameters of 10, 20, and 60 in. (250, 510, and 1520 mm) . • Gate valves are required for each pipe according to the applicable security regulations. The 60 in. valve, plus accessories, weighs about 140 kN (31.5 kip), and the 20 in. valve, plus accessories, weighs about 15 kN (3.4 kip). • Platforms are required for access valves, instruments, and maintenance. These requirements generate significant seismic demandson the structure (Fig. 1) . In this particular case the client requested that the structure be precast concrete to minimize cast-in-place concrete work and to accelerate construction. These circumstances, added to the fact that the facility is located in a high seismic zone in Mendoza, Argentina, required the designer to use connection details with good seismic performance, which should simplify the erection. Table 1 summarizes the main seismic parameters, and

FAQs

What is the primary structural system of the pipe rack described in the case study?

The pipe rack uses precast reinforced concrete moment frames transverse to the load direction, with shear keys formed by simply supported precast reinforced concrete beams, and steel V-bracing for longitudinal load resistance.

Why was minimizing cast-in-place concrete important for this petrochemical project?

Strict safety guidelines in petrochemical facilities restrict work permits and make on-site concrete operations harder, so precast systems help reduce permit-related complications and working at heights.

How are flare gas and related pipelines considered in the project’s operational context?

Flare gas pipelines are described as gravity-fed due to highly corrosive condensate, and gas-gathering pipelines route flammable gases to flare stacks for controlled burning under environmental and hazard-reduction requirements.

Oct 24, 2026

Upload by Terk