Design Guidelines for Therapeutic Gardens

This paper is a systematic review of quantitative studies conducted on the benefits of visiting gardens and gardening therapy for people with dementia (PWD) in an effort to assess the effectiveness of such treatments and obtain information on the most appropriate garden design for this population. This review followed the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA) guidelines. Four databases were searched (PubMed, Web of Science, PsycINFO, Scopus), with no time limits. Out of a total of 480 articles considered, 16 studies were selected for review. In all but two of the studies examined, gardening therapy and the use of therapeutic gardens induced psychophysiological improvements in PWD. The areas showing the greatest effects were Engagement, Agitation, Depression/Mood, Stress, and Medication. It also emerged that interest in this sphere has been growing in the last decade, but there is still a shortage of empirical evidence of the beneficial effects of therapeutic gardens in relation to the type and severity of dementia, and of garden design guidelines. Despite the limited number of studies investigated, the review confirmed the benefits of gardening and therapeutic gardens in PWD. There is nonetheless a need to conduct more quantitative research to support currently-available evidence and generate more information, focusing on garden design criteria, in-garden activities, the type and severity of dementia examined, and effects on caregivers as well as on PWD.

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Flexural design of precast, prestressed ultra-high-performance concrete members

PCI Journal ◽

10.15554/pcij65.6-02 ◽

2020 ◽

Vol 65 (6) ◽

pp. 35-61

Author(s):

Chungwook Sim ◽

Maher Tadros ◽

David Gee ◽

Micheal Asaad

Keyword(s):

Prestressed Concrete ◽

High Performance ◽

High Performance Concrete ◽

Limit State ◽

Design Guidelines ◽

Design Tool ◽

Supplementary Cementitious Materials ◽

Ultra High Performance Concrete ◽

Concrete Members ◽

Cylinder Strength

Ultra-high-performance concrete (UHPC) is a special concrete mixture with outstanding mechanical and durability characteristics. It is a mixture of portland cement, supplementary cementitious materials, sand, and high-strength, high-aspect-ratio microfibers. In this paper, the authors propose flexural design guidelines for precast, prestressed concrete members made with concrete mixtures developed by precasters to meet minimum specific characteristics qualifying it to be called PCI-UHPC. Minimum specified cylinder strength is 10 ksi (69 MPa) at prestress release and 18 ksi (124 MPa) at the time the member is placed in service, typically 28 days. Minimum flexural cracking and tensile strengths of 1.5 and 2 ksi (10 and 14 MPa), respectively, according to ASTM C1609 testing specifications are required. In addition, strain-hardening and ductility requirements are specified. Tensile properties are shown to be more important for structural optimization than cylinder strength. Both building and bridge products are considered because the paper is focused on capacity rather than demand. Both service limit state and strength limit state are covered. When the contribution of fibers to capacity should be included and when they may be ignored is shown. It is further shown that the traditional equivalent rectangular stress block in compression can still be used to produce satisfactory results in prestressed concrete members. A spreadsheet workbook is offered online as a design tool. It is valid for multilayers of concrete of different strengths, rows of reinforcing bars of different grades, and prestressing strands. It produces moment-curvature diagrams and flexural capacity at ultimate strain. A fully worked-out example of a 250 ft (76.2 m) span decked I-beam of optimized shape is given.

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