The phrase "adding to the strain" is correct and usable in written English.
It can be used when discussing factors that increase pressure or difficulty in a situation.
Example: "The unexpected expenses were adding to the strain of managing the household budget."
Alternatives: "increasing the pressure" or "exacerbating the stress."
Global warming, some experts suspect, may be adding to the strain.
Teena vehemently denied to her mother that she was a lesbian, adding to the strain between them.
[C7.] Tax Shelters Cut Revenue of States Tax sheltering has cost states more than a third of their revenue from taxes on corporate profits, adding to the strain on state finances across the country, a study showed.
With social care departments across the country overwhelmed by increased demand and diminishing resources, tasks like multiple form-filling and other bureaucracy for care assessments that would be allayed by smoother IT systems are adding to the strain.
Labour has blamed the cuts in social care and the difficulty in getting GP appointments but some argue the increase in cold weather leads to more viruses adding to the strain on hospitals.
Such an approach may save lives, but has the potential to more than double the number of intravenous treatments delivered to the population of patients with early-stage breast cancer, hence adding to the strain on resources.
And since China became a net importer of oil in 1993, most of its imports have been shipped in, adding to the strains in the oil tanker industry.
Apart from adding to the strains in those countries (especially in Macedonia, where tension between local Slavs and Albanians is intense), Mr Milosevic was graphically reminding NATO that hundreds of thousands more Kosovars are still within his grip.
The migration of thousands of private insurance holders to state-sponsored schemes has added to the strain.
